FAQ

PDF SealBox is used to add visible stamps, signature images, approval marks and cross-page seals to PDF files. It is useful for contract circulation, receipt marks, internal approvals, bid documents, finance records and administrative file handling. It adds visible page marks and does not replace certificate-backed digital signatures, notarization or identity verification.

The regular browser stamping workflow is designed to process PDFs and stamp images locally in your browser whenever possible, instead of sending files to a remote conversion server. The website still needs to load scripts and basic resources. For highly sensitive contracts, financial records, HR files or regulated documents, an offline desktop workflow is usually the safer choice.

No. A visible PDF stamp is an image or text mark placed on the page for human review and office workflows. A digital signature usually involves certificates, hashing, signer identity and tamper detection. If your workflow requires certificate-backed signing, use a compliant electronic signature or digital certificate service.

Yes. You can upload your own transparent PNG, JPG or other common image file as the stamp source, then adjust placement, scale, opacity and rotation in the preview. A transparent, high-resolution PNG with clean edges usually gives the best result and keeps the PDF text easier to read.

Transparent PNG is usually the best choice. It avoids the white rectangle that often appears with JPG images and looks cleaner on contracts, invoices, approval forms and scanned pages. JPG can still work, but the background may cover nearby text unless the image has already been prepared carefully.

Yes. You can apply a regular stamp to all pages, selected pages or rule-based page ranges, then check the preview before exporting. For batch stamping, always review the first page, last page, landscape pages, scanned pages and text-heavy pages to make sure important content is not covered.

A cross-page seal splits one stamp across page edges so a multi-page document can be checked visually. It is often used for contracts, bid documents, quotations and file bundles. PDF SealBox provides the visible image layout; it does not verify the authenticity or legal effect of a printed document.

The web version needs the website to load first and is suited to browser workflows. The Windows desktop version is designed for offline processing after the initial license activation. For documents that must not be uploaded or handled online, the desktop version is usually more appropriate.

Local browser processing means PDF parsing, preview rendering and export are mainly performed by scripts running in your own browser, instead of by a remote conversion server. This reduces the chance that files leave your device. You should still consider browser extensions, network environment, device security and company policy.

The regular browser workflow is intended not to store user PDF files. Files are used in the current browser session for preview and export. For extra caution, close the page after use, remove downloaded temporary files, and use the offline desktop version for sensitive documents.

The tool can technically process those PDFs, but you must confirm that you have permission to handle the files and that the output meets your business and compliance requirements. PDF SealBox provides stamping layout and export functionality only. It does not replace legal review, company approval or an electronic signing platform.

Mobile browsers can use the same general browser workflow, but small screens make precise placement and multi-page checking harder. Mobile is fine for quick, low-risk tasks. For sensitive documents, many pages or precise stamp placement, desktop browser or offline desktop processing is recommended.

Privacy depends on more than whether the tool uploads files. Browser extensions, network policies, device state and operator habits also matter. Offline desktop processing reduces uncertainty from the web environment and is better suited to contracts, finance, HR, audit and regulated files.

No, not for important documents. Public computers may keep browser cache, download history, account sessions or unknown extensions. If you must use one, avoid sensitive files and remove downloaded files and browser data after use.

Preset stamps are useful for quick status marks such as PAID, RECEIVED, APPROVED, REJECTED, DRAFT, VOID and CONFIDENTIAL. They are intended for internal workflow, review, archiving and collaboration. The meaning of a preset stamp should always follow your own business process.

Preset stamps are generated by the tool and are best for general status labels. Custom images come from files you upload and are better for company seals, signatures, department marks or custom branding. Custom images are more flexible, but you must make sure you are allowed to use them.

Use a clean image with transparent edges and at least 472 pixels in width or height. Very small images may look blurry after export, while extremely large images can slow down processing. For most office stamps, an image around 500 to 1200 pixels wide is enough.

This usually means the uploaded image does not have a transparent background, or it was saved as JPG. Use a transparent PNG or remove the background with an image editor before uploading. PDF SealBox does not automatically decide which parts of your image should become transparent.

Yes. You can place a handwritten signature image on PDF pages as a visible mark. Use a transparent PNG and check the position, size and clarity before exporting. A signature image is not the same as signer identity verification or certificate-backed e-signing.

Preset stamps use built-in color styles, while custom image color comes from the uploaded file. If you need an exact color, prepare the image in an image editor first and then upload it to PDF SealBox.

PDF pages can have different sizes, orientations, scan margins and text density. The same stamp settings may look different across pages. Previewing helps catch covered text, wrong position, oversized stamps or unsuitable opacity before you create the final file.

When the regular stamp is enabled, clicking the PDF preview sets the regular stamp position for the current page. The position is typically stored as page-relative coordinates and mapped back to the real PDF page size during export. Cross-page seal placement is controlled mainly by edge, position ratio and split settings.

Yes. Depending on the available range controls, you can stamp all pages, skip the first page, use a single page, choose odd or even pages, or enter a custom range. After setting the range, use Previous and Next to verify which pages are actually stamped.

A PDF may contain mixed page sizes, landscape pages or scanned pages with uneven margins. Even with the same settings, the visual result can vary. Review representative pages and adjust individual page positions when needed.

Browser zoom should only change what you see on screen. It should not change the exported stamp position or scale, because export should be calculated from the real PDF page size rather than screen pixels. Still, it is good practice to open the exported file once before sharing it.

Large PDFs, scanned pages, high-resolution images, complex vector drawings and many pages all increase rendering time. Browser performance, memory and display scaling can also matter. If you process large files often, use a faster computer or the offline desktop version.

Cross-page seals are useful for multi-page contracts, bids, quotations, audit files, policy documents and file bundles where people need to visually check page continuity. Single-page documents usually do not need a cross-page seal. For long files, inspect the split result before exporting.

Position ratio controls where the cross-page seal sits along the selected page edge. A smaller value moves it toward one end of the edge, while a larger value moves it toward the other end. The exact direction depends on whether the selected edge is left, right, top or bottom.

Max sections limits how many pieces a full cross-page seal can be divided into. For many pages, a higher value can cover more pages. For shorter documents, a smaller value is usually enough. The goal is clear, continuous edge pieces without harming readability.

Yes. You can configure the cross-page seal range so only specific page groups are included, such as selected pages, odd or even pages, or a custom range. When only part of a document is included, check the sequence carefully so the visual split still makes sense.

Yes. A regular stamp places a complete mark inside the page, while a cross-page seal places split pieces along page edges. If both are enabled, adjust opacity or placement so the document does not become visually crowded.

Not by itself. It provides a visual clue for manual review, but it does not replace digital signatures, hash verification, tamper-proof systems or document custody procedures. Use stronger security controls when tamper resistance is required.

That depends on the original PDF and export method. A visible stamp becomes part of the exported page content, but it does not guarantee that the file cannot be edited. If you need editing restrictions, combine PDF permissions, digital signatures or a document management system.

Exporting adds stamp images, page objects or rendered content to the PDF, so file size may increase. Large stamp images, scanned PDFs and stamping many pages can make the increase more obvious. Compressing the stamp image before upload can help.

Some workflows may rasterize the page, and some PDFs are scanned images from the beginning. Once page content becomes an image, text cannot be edited like normal PDF text. Check the exported file before using it in workflows that require selectable or editable text.

A protected PDF usually requires the correct password or permission before it can be processed. You should not attempt to bypass document protection. Even if you can open the file, confirm that you are allowed to modify and export it.

PDF files can contain special fonts, encryption, damaged objects, huge images or non-standard structures. If a file fails, try opening it in a mainstream PDF reader and saving a new copy, or test with a smaller page range first.

Check the file name, page range, stamp source, stamp scale, opacity, rotation, cross-page seal edge and key page positions. Before sending the file outside your organization, confirm that important text is not covered and your business approval requirements are met.

No. The tool only places the image or preset mark you choose onto PDF pages. It does not judge seal ownership, authorization scope or legal effect. You are responsible for using files and seal images only when you have the right to do so.

Do not use any tool to forge, alter or misuse official documents, certificates, official seals, anti-counterfeit labels or third-party marks. PDF SealBox is intended for lawful office workflows, such as internal review, file organization, visible status marks and documents you are authorized to process.

No. Legal effect depends on the document, signing workflow, parties, evidence chain, applicable law and business context. PDF SealBox does not provide legal advice and does not guarantee that a stamped result will be valid in any specific situation.

Make sure you are authorized to use the seal image and follow your organization stamp management rules. Do not share seal images with unrelated people or use them on unauthorized documents. For important files, keep approval and operation records.

No. PDF SealBox is not a notary, certification authority, electronic signature provider or certificate authority. It provides visible PDF marking and office document handling features.

If your workflow requires electronic signatures, digital signatures or identity verification, use a signing platform or certificate service that meets your legal and business requirements. PDF SealBox can support visual marking, but it cannot replace a formal signing system.

The web version is convenient for quick browser use and common local browser processing. The Windows desktop version is better for offline work, batch files, fixed office computers, sensitive documents and workflows that need more stable local operation. Both aim to make PDF stamping easier.

Activation is used for license management. The desktop version usually needs online verification once during first installation. After activation, the local license can be verified on the same computer for offline use. Moving to another computer follows the license rules.

The trial is meant to help users check whether the tool works with their PDFs, seal images and workflow. Licensed use is more suitable for long-term and offline processing. Current limits should be confirmed in the software interface and purchase notes.

PDFs vary in page size, fonts, scan quality and permission settings. Testing with a sample file helps confirm preview, placement, scale, cross-page seal splitting and export behavior before you process formal documents.

Check whether the PDF is very large, scanned, image-heavy or made of complex vector content. Closing other memory-heavy apps, processing fewer files at once or using a faster computer can help. For repeated batch work, the desktop version is recommended.

Include your operating system, browser or software version, PDF page count, general file type, stamp image format, exact steps and the visible error. Do not send sensitive original files unless you have removed private information or created a safe test file.