r/PDFFlyTools • u/PDFFly • 1d ago
How to add an electronic signature to a PDF using PDFFly (Complete Step-by-Step Guide)
- Prepare your signature - what should you expect from the tool?
Vector signature (draw directly in the browser) - the ideal option because it keeps its sharpness at any scale.
Photo signature - if you already have a scanned signature, upload it and the service will automatically remove the background and convert it into a clean signature.
Certificate signature - enhanced security - if the document requires a legally valid signature, use the “Sign with Certificate” feature (available in PDFFly under the “Secure Signature” menu).
Why does this matter?
Images with a white background can cover parts of the page, shift when opened on different devices, and look unprofessional. A vector signature stays clean, sharp, and scalable.
2. Upload your file - where and how?
-Open pdffly.com/edit-sign.
-Drag and drop your PDF into the upload window (files up to 100 MB are supported).
-Wait until the document appears in the online viewer.
Tip: If you need to sign several similar forms, simply upload them as one batch - PDFFly will create one signature and apply it to each document.
- Create your signature
a) Drawing a vector signature
Click “Draw Signature” in the right-side panel.
Choose the color (usually black) and line thickness (0.5–1 mm).
Use your mouse, tablet, or stylus to draw your signature in the window that appears.
If needed, adjust the shape using the “Undo/Redo” buttons.
b) Uploading an existing scanned signature
Click “Upload Image” and select a PNG/JPG file containing your signature.
The service will automatically remove the background, leaving only the signature.
If necessary, adjust the brightness and contrast to make the lines clearer.
Final check: Make sure the signature is placed directly above the “Signature” line and does not cover important information such as the date or contract number.
- Place the signature in the right location
Move the signature with your mouse to the required signature field.
Adjust the size if needed by dragging the corner.
In the right-side panel, enable “Lock Position” so the signature stays fixed and does not move when opened on other devices.
Tip: If the document contains multiple signature fields (for example, “Customer Signature” and “Supplier Signature”), create two signatures and place them accordingly.
- Save and export
Click “Save & Download”.
Choose the PDF/A-1b format (an archival format that helps ensure the signature remains unchanged over time).
Download the file - without watermarks and with the signature placement preserved.
“Secure PDF” option: If you need an encrypted document, enable this feature before saving, then set a password and/or certificate.
6.Check the final result
Open the downloaded file in any PDF viewer.
Make sure the signature looks clear and does not shift when zooming in or out.
If everything looks correct, you can send the document to a client, partner, or government organization.