How to Sign a PDF Securely

Signing a PDF should be quick, but "secure" is the part that matters. A signature is only as trustworthy as the document around it — if anyone can alter the file afterward, the signature means little. This guide covers signing in Falcon PDF and, just as importantly, how to lock the finished document so it stays exactly as you signed it.

Types of PDF signatures

• Drawn / electronic signature — a handwritten mark you draw, type or import. Fast and widely accepted for everyday agreements.
• Image signature — a scanned photo of your signature placed on the page.
• Password protection — not a signature itself, but the layer that keeps a signed file from being edited. Pair it with any signature above.

Create your signature

1. Open the PDF and choose Sign from the toolbar.
2. Create a signature by drawing with your finger or stylus, typing your name in a signature font, or importing an image.
3. Save it to reuse on future documents.

Place and size it

• Tap where the signature belongs and drag the handles to size it.
• Add the date beside it using Add Text.
• Zoom in to align precisely with the signature line.

Protect the signed file

Once signed, protect the document so the signature can't be moved or the content altered. Falcon PDF offers two complementary safeguards:

Set a password and permissions

1. Open the protect tool.
2. Set an open password, a permissions password, or both.
3. Choose which actions to restrict — editing, copying, printing.
4. Save the protected copy and share it.

Security best practices

• Flatten the signature before sending so it can't be repositioned.
• Use a strong, unique password when the document is sensitive.
• Send the password over a separate channel from the file itself.
• Keep an unsigned master copy in case you need to reissue.
• Consider a visible watermark for drafts so signed and draft versions are never confused.

FAQ

Are electronic signatures legally valid? In many countries, yes, for most agreements — but requirements vary. For high-stakes contracts, confirm whether a certified digital signature is required.

Can I sign on my phone? Yes. Drawing with a finger or stylus works on iOS and Android, and everything syncs across desktop. Get Falcon PDF to start.