Three ways to stamp a PDF
There are three main ways to put a hanko on a PDF. They differ in effort and in how strongly they show that you created the document.
| Method | Effort | Suits |
|---|---|---|
| 1. Print, stamp and scan | High (needs a printer and scanner) | Documents that must be stamped like paper |
| 2. Add a digital seal (an image of the stamp) | Low (free tools, done in a minute) | Quotes, invoices, internal documents |
| 3. Use an e-signature / e-contract service | Needs a service account and setup | Contracts and other documents where proof matters |
Method 1: Print, stamp and scan
Print the PDF, press your actual hanko on it, then scan it back into a PDF. It takes time, but it’s the same as stamping paper, so it’s the safe choice when you’re asked for a “stamped document as a PDF”.
- Print the PDF and stamp it in the right place
- Scan it with a scanner or your phone to make a PDF
- Fix the page orientation and file size, then submit it
No scanner? Use the document scanner in the iPhone Files app, or turn photos into a PDF. If the file gets too large, compress it to fit the upload limit.
Method 2: Add a digital seal to the PDF
A digital seal (denshi inkan) is an image of a stamp impression. You place the image where you need it on the PDF, with no printing or scanning, so it’s the easiest option.
With our Hanko Stamp Maker, you type your name to create a round personal seal (mitome-in) or a date stamp, and place it anywhere on a PDF. You can also save it as a transparent PNG to use in Word or Excel.
- Choose the type (personal seal or date stamp) and enter your name
- Choose the font, color and size
- Select your PDF and tap where the stamp should go
- Tap the button to create the stamped PDF and save it
Keep in mind that a digital seal is just an image: anyone can make or copy the same one, so it doesn’t prove that you stamped it. Check your company’s rules on whether digital seals are accepted for internal documents.
Method 3: Use an electronic signature or e-contract service
An electronic signature is a technical mechanism defined in Japan’s Electronic Signatures Act (Act on Electronic Signatures and Certification Business). The Act defines it as a measure that meets both of these requirements:
- It shows that the information was created by the person who applied the measure
- It makes it possible to check whether the information has been altered
Article 3 of the Act also states that an electronic document carrying a qualifying electronic signature by the person themselves is presumed to be authentic (created by that person). For contracts, where you may later need to show who created the document, an e-contract service that supports electronic signatures is the right fit.
Note that a handwritten signature added with our Sign PDF tool, or a stamp added with Hanko Stamp Maker, is a visual signature or seal. It is not an electronic signature in the sense of the Act.
Does a contract need a stamp at all?
In its “Q&A on Seals” published in June 2020, Japan’s Cabinet Office, Ministry of Justice and Ministry of Economy, Trade and Industry explain that a contract is formed when the parties agree, and that unless a specific rule says otherwise, a written document and a stamp are not required for the contract to be formed. Not stamping does not affect the contract’s validity.
On the other hand, under Article 228(4) of the Code of Civil Procedure, a document stamped by the person themselves is presumed in court to have been created by that person. The Q&A notes that this effect is limited, and that authorship can also be shown in other ways, for example:
- Keeping email records with the other party (addresses, message text, dates and times)
- Keeping the identity information checked before starting business and the exchanges that led to the contract
- Using electronic signatures or electronic authentication services
If a law or an agreement with the other party requires a stamp, you need to follow it. When in doubt, ask the recipient.
Which method should you choose?
A rough guide by type of document. In the end, follow the recipient’s, client’s or company’s rules.
- Internal requests and circulated documents: a digital seal (if your company accepts it)
- Quotes, invoices and delivery notes: a digital seal, and keep the email records too
- Contracts and other important documents: an e-contract service with electronic signatures
- When asked for a “stamped document”: print, stamp and scan
Your PDF is never uploaded
With our tools, your PDF isn’t uploaded to a server; it’s processed only on your device. You can stamp confidential documents such as contracts and invoices with peace of mind.