pdfMB

Sign PDF

Draw, type or upload your signature, then place it on the page. Your file stays on this device.

Create your signature

Ink color

This is a picture of your signature, not a digital signature that can be verified. pdfMB does not guarantee that it is legally valid.

  • No uploadYour file stays on this device.
  • Your original stays as it isYou download a new copy. Your file is never changed.
  • Free, no sign-upNo account and no daily limit.

What happens to your file and your signature

Everything below happens inside your browser, on your own device. The PDF and your signature are never uploaded, so nobody else, including us, can see them.

  1. Your browser opens the PDF and draws the pages with pdf.js, the PDF viewer built into Firefox.
  2. A drawn signature is kept as the lines you drew, with the thickness changing as you write. It is saved into the page as vector lines, so it stays sharp when someone zooms in.
  3. A typed, uploaded or photographed signature is saved as a picture with a see-through background. For photos and scans, the paper color is removed so only the ink is left.
  4. The signature, date and name are written into the page itself, not added as a separate comment layer that can be clicked away or deleted in a PDF editor.
  5. The rest of the file is left as it was: the text you can select and search, links, bookmarks and form fields.
  6. If you tick “Remember on this device”, the signature is stored in this browser’s local storage. Nothing is stored unless you tick it, and “Forget saved signature” deletes it.
In short
  1. Choose a PDF
  2. Create your signature
  3. Tap the page to place it
  4. Press “Save signed PDF” and download

How to sign a PDF

  1. Choose a PDF. The first page opens large, with small page previews below it.
  2. Press “Create signature” and draw it with your finger, a pen or the mouse. You can also type your name, upload a picture of your signature, or take a photo of it.
  3. Tap the page where the signature should go. Drag it to move it, drag a corner to resize it, and use the page previews to go to another page.
  4. Add the date, your name, your initials or a check mark if the document asks for them.
  5. Press “Save signed PDF” and download the file. “Back to editing” keeps everything in place if you want to change something.

When people use it

Forms and applications

Sign a job application, a school form or a lease that was sent as a PDF, without printing and scanning it.

Initials on every page

Some contracts ask for initials on each page. Place them once and press “Repeat on all pages”.

Quotes and receipts

Sign a quotation or delivery note and send it back straight from your phone.

Documents in Thai

Type your name in Thai in a handwriting-style font, and add the date in the Thai format with the Buddhist year.

What it can’t do

  • This is an electronic picture of your signature, not a digital signature with a certificate. Nobody can use it to check who signed or whether the file was changed later. If a document must have a certified digital signature, use a service that issues one.
  • pdfMB does not guarantee that a signed file will be accepted. Whether a picture signature is enough depends on the law where you are and on whoever receives the document.
  • Any digital signature already in the PDF stops being valid once the file is changed, including by adding a signature here.
  • The handwriting style for typed names covers Latin and Thai letters. Names in other scripts are drawn with your device’s font.
  • Background removal works best with dark ink on plain white paper. Shadows, lines or colored paper may leave marks, so check the preview.
  • Password-protected PDFs, and PDFs whose owner has blocked editing, can’t be opened.

Questions about signing PDFs

Is a signature made here legally binding?

It depends on the country and on who receives the document. Many everyday documents accept a signature image, but some require a certified digital signature. pdfMB only adds a picture of your signature and cannot guarantee legal validity.

Can someone remove my signature from the PDF?

It is not a separate layer or comment that can be clicked away. It is written into the page content, like a stamp. A person with a PDF editor can still edit any part of a page, though, so this is not tamper protection.

Is my signature stored anywhere?

No, unless you tick “Remember on this device”. Then it is kept only in this browser, on this device. It is never uploaded. Press “Forget saved signature” to delete it.

Can I sign every page at once?

Yes. Place the signature or your initials on one page, then press “Repeat on all pages”. To sign just a few pages, use “Copy to page…” and type the page numbers, such as 2, 4-6.

How do I make the white paper disappear in my photo?

Use “Upload” or “Photo”. pdfMB measures the paper color across the photo and removes it, leaving only the ink. Dark ink on plain white paper gives the cleanest result.

Can I add the date in Thai?

Yes. On the Thai page the date is written the Thai way, for example 20 ตุลาคม 2569, with the Buddhist year. You can edit the text before saving.