How to stamp a PDF: Add a seal in addition to the signature

Key points of this article

First ask whether the other party wants a handwritten signature, a seal, or both, and then decide whether to parallel or substitute.
Try to use a PNG with a transparent background for the seal image. Only the imprint should be retained. The edges should be clear and can still be identified after enlarging the image.
After inserting the seal image in the PDF editor, confirm the position page by page to avoid suppressing the main text and key figures.
Finalize the content before stamping; if you change the text after stamping, the seal and content may not match.
Whether the seal is accepted depends on the purpose and the other party's requirements. Official documents must be confirmed in advance.

Many people will encounter this situation when dealing with contracts, reimbursement forms or application materials: there is already a handwritten signature on the PDF, but the other party also requires a seal; or the other party only needs a seal and no signature. At this time, "How to get a PDF signed and stamped" becomes a different problem from ordinary signatures. The signature solves the problem of "who confirmed the content", while the seal solves the problem of "which unit or identity approved the content". The position, size and purpose of the two on the page may be different.

This article is for anyone who needs to add a stamp to a PDF while retaining or replacing the signature. After reading, you will know how to judge whether to stamp or not, how to prepare the stamp image, how to put the stamp in the correct position in the PDF editor of the OmniDoc desktop client, and what checks to do before and after exporting.

How to get signature and seal of pdf? One sentence conclusion

Stamping and signing are not always an either/or option. The judgment is mainly based on the other party's requirements and the purpose of the document. The following table can be used as a starting point.

your situation	Recommended practices	reason
The other party asked for "signature and seal"	The signature and seal are placed side by side, each in the designated position	The two represent the person in charge’s confirmation and the unit’s confirmation respectively, and both are indispensable.
The other party only requires a seal, not a signature.	Add only the seal image and leave the signature area blank	Avoid unnecessary confusion caused by extra handwritten signatures
The other party only needs a handwritten signature, not a seal.	Only signature, no seal	More stamps may cause the other party to ask for re-checking.
Internally archived or self-recorded documents	It can be signed or noted in the document, and a seal can be added as needed.	Seal requirements for internal transfers are usually lower, but still subject to unit regulations.
Formal contracts, documents involving rights and obligations	Confirm with the other party in advance whether they can accept scanned seals or electronic seals	Effectiveness depends on the intended use and the other party’s regulations and cannot be taken for granted.

Before you start: Confirm these points first

Before you start, take a few minutes to confirm the following things to avoid rework.

Confirm the specific requirements for the seal. Some units only accept official seals, while others accept contract-specific seals; in some cases, a seam seal or a designated page seal is required. These requirements determine which kind of seal image you want to prepare and where to stamp it.
Confirm content has been finalized. If you correct the text after stamping, the seal and content may not match, which can easily cause disputes in contracts and approval materials. First check the text, amount, and date, and then stamp it.
Prepare a clear picture of the seal. Use a scanner or mobile phone to take a photo of the stamp, crop it until only the imprint remains, and save it as a PNG. A transparent background makes it easier to superimpose on the page; if the edges of the imprint are blurry, they will not be visible clearly after magnification and need to be rescanned.
Confirm the type of PDF. If the document is printed on paper and then scanned, the text often cannot be selected. You can try dragging and selecting a piece of text in the PDF: if it can be selected, it means it is an editable or searchable text version; if it cannot be selected, it is probably a scanned copy. At this time, the seal can be added directly, but if you want to modify the text, you need to do OCR first.
Ready environment for downloading and opening. Stamping needs to be done in the OmniDoc desktop client, the download address is download.omnidoc.top. The translation function on the web page does not include a PDF editor and cannot be used for stamping.

Steps to stamp PDF in OmniDoc

The following steps take "adding a seal to the signature" as an example. If you only need a stamp and no signature, just skip the signature part.

Prepare the seal picture. Scan or take a photo of the seal and then crop it into a PNG file, making sure the edges are complete and the color is clear. Use a recognizable name for the file name, such as "Company Seal.png", for easy selection later.
Open the desktop client and load the PDF. Start the OmniDoc desktop client, enter the PDF editor, and open the original file that needs to be stamped. It is recommended to save a copy first and keep the original as a draft.
Turn to the page that needs to be stamped. Confirm which page and location it is. If the contract requires every page to be stamped, or if it is to be stamped at the seams, list all page numbers in advance.
Select the signature function. Find the signature-related functions in the PDF editor, which are used to add signature content on the page.
Import the prepared stamp image. Select Import Image in the signature content options and load the PNG file prepared in step 1. If you only need a seal, add only the seal and no handwritten signature.
Place it at the target location. Place the seal where it needs to be stamped, usually at the inscription, near the date, or at the designated seam position. Be careful not to suppress the main text, amount and table lines, otherwise it may be considered that the content has been altered.
Check and supplement page by page. Turn to each page that needs to be stamped and repeat steps 5 and 6. When the signature and seal are juxtaposed, make sure they do not block each other.
Save as new PDF file. After completion, save it as a new file. You can add "stamped" or other instructions to the file name to distinguish it from the original.

Check each item after completion

After the stamping is completed, it is recommended to check the documents item by item according to the form below before sending it to the other party.

Check items	How to see it	What should you do if there's a problem?
Check if the stamp is clear	Zoom in on the page to see if the stamp edges and text are intact	If the stamp is blurry or missing a corner, scan again and use a clearer image to stamp it again
Whether the location is appropriate	Check whether the main text, amount, table lines, or page numbers are being pressed down	If the position is incorrect, readd the seal to ensure it falls in a blank area or the signature area
Check whether the page count is complete	Flip through each page and compare the page numbers to the other party's requirements	Patch the missing pages; For cross-seam stamps, ensure that all page stitching is complete
Check whether the signature and seal are listed side by side correctly	Check if the signature and seal are in the designated spot and if they block each other	Adjust the positions of both and add them separately if necessary
Check if the device displays normally	Open the file on another computer or phone and see if the stamp is displayed	If it does not show, re-export; If necessary, send the final documents to yourself for inspection
Whether the content is consistent with the final version	Compare the text, amount, and date against the final version	If inconsistencies are found, modify them first and then stamp them; do not directly modify documents that have already been stamped

If the other party asks you to submit the document for someone else to sign instead of stamping it yourself, you can use OmniDoc's signature request feature to send the PDF to the other party and have them sign online. This method is different from stamping oneself and is suitable for occasions where confirmation is needed.

📝 Summary

To determine "how to sign and stamp a PDF," first check whether the other party wants to sign and stamp, or both; Then prepare a clear seal image, insert it into the PDF editor in the OmniDoc desktop client, place it in the designated location, and finally verify page by page and save it as a new file. The validity of official documents shall be subject to the regulations of the other party and relevant institutions.

❓ Frequently Asked Questions (FAQ)

1. Does adding a stamp image only to a PDF have legal effect?

Validity depends on the purpose of the document, the type of seal, and the requirements of the other party, and cannot be generalized. For documents involving contracts or formal approval, try to confirm in advance whether scanning or electronic seals are accepted, and consult relevant professionals if necessary.

2. What format should I use for seal images best?

PNG is commonly used; when the background is transparent, it is overlaid on the page without being blocked by a white background. When taking photos or scanning, ensure even lighting and clear prints; only the stamp is left intact during cutting.

3. Can I still edit the PDF after stamping?

You can modify it, but after modification, the seal and content may no longer correspond, and the other party may not accept it. It is recommended to finalize the content first, then stamp it uniformly; If there have been any changes, try to restamp and keep the versions before and after the revisions.

4. What should you do if you don't have a physical seal on your hand?

Do not imitate others' official seals or privately carve seals, as this may pose legal risks. If only internal records are kept, you can sign or indicate the handling information in the document; Documents submitted externally must be stamped by authorized personnel according to unit regulations.

5. Can scanned PDFs also be stamped?

Yes, you can. You can also add a stamp image to the scan, but text cannot be directly selected. If you want to modify the text later, you need to use OCR recognition before editing the content.

Open OmniDoc and initiate a PDF online signing