What a watermark is for
A watermark is a word or a short line that sits faintly across a page. People use it to show what state a document is in, such as DRAFT or COPY, to show that it is private, such as CONFIDENTIAL, or to mark who a copy was made for, with a name and a date.
Choose good text
- Short words work best, such as DRAFT, COPY, PAID or CONFIDENTIAL.
- Use one line, up to 60 characters. For a copy made for one person, a name and a date is a good choice.
- Letters, numbers and common symbols work, including accented letters used in European languages. Chinese, Arabic and emoji cannot be written with the built-in font.
How to do it with Velfile
- Open Add Watermark to PDF and choose your PDF. Files up to 100 MB are accepted.
- Type the Watermark text.
- Pick the Direction: Diagonal fits most documents, and Straight gives a neat line across the middle of the page.
- Pick the Colour (gray, red, blue or black), the Size (small, medium or large) and the Strength.
- Leave Pages to mark empty to mark every page, or type pages such as 1-3 or 2, 5.
- Press Add watermark, then Download PDF.
Your PDF is processed in your browser. It is not uploaded to a server, and your original file does not change, because the watermarked copy is a new file.
Keep the page easy to read
A watermark that is too strong makes the text underneath hard to read. A strength of around 20 to 30 percent works well for most documents, and a gray colour is the least distracting. If the page still looks crowded, make the watermark smaller or change it to Straight.
Can a watermark be removed?
The watermark is drawn onto the page. It is not a layer you can switch off in a normal PDF reader. Someone with a PDF editor may still be able to remove it, so do not use a watermark as your only protection for a sensitive document. It is a clear label, not a lock.
A few good uses
- Mark a proposal or a contract as DRAFT until it is final.
- Mark a scan of an ID card as For job application only, 14 Oct 2026, so it is clear what the copy was meant for.
- Mark a paid invoice as PAID.
- Mark a file as CONFIDENTIAL before you send it to a client.
Before you send it
Open the new PDF and look at a few pages. If the file is too large to send, shrink it with Compress PDF. If the document also needs page numbers, add them with Add Page Numbers to PDF.
If something does not work
- “Type the watermark text first”. The button stays unusable until the Watermark text box has something in it.
- “This text has characters the built-in font cannot write”. The text has a character the built-in font does not have, such as a Chinese character or an emoji. Use letters, numbers and common symbols instead.
- “Pages must be between 1 and …”. The range in Pages to mark goes past the last page. Check the page count shown for your file.
- “Password protected or could not be read”. Velfile cannot open a PDF with a password. Save a copy without the password in the program that made it, then try again.
- The watermark is cut off or too big. Choose a smaller Size, or shorten the text. A long line at a large size can run past the edge of the page.
The watermarked file is a new copy, so you can run it again with other settings until it looks right. Your original PDF stays as it was.
Last updated: 17 October 2026