Sign PDF Online
Securely & Instantly
Sign your contracts, invoices, and documents online. Draw your signature, type your name, or upload an image file. Safe, legal, and 100% free.
Professional Electronic Signatures for PDF Documents
Contracts, lease agreements, non-disclosure forms, and business invoices require signatures to take legal effect. Historically, signing required printing the document, signing it by hand, scanning it back into the computer, and emailing it back. This workflow is slow, wasteful, and requires access to physical office hardware. Electronic signatures solve this bottleneck, allowing you to sign documents instantly.
ZenPDF provides a secure, web-based Sign PDF tool. Our editor loads your PDF inside a secure browser session. You can draw your signature using a trackpad, mouse, or touchscreen; type your name using curated cursive font styles; or upload an image file of your handwritten signature. You can resize and place the signature block on any page, then flatten the PDF to seal the file.
Security and compliance are critical for electronic signing. ZenPDF does not store your signature profiles, credentials, or documents on our servers. All communication is encrypted using SSL. Signed documents are automatically and permanently deleted from our servers after 1 hour, keeping your agreements completely private.
How It Works in 3 Steps
Add secure electronic signatures to your contracts in just a few clicks.
Upload Document
Drag and drop your PDF agreement into our secure signer box or click to select the file from your local drive.
Create & Position
Draw your signature, type it using cursives, or upload a signature image. Position it on the correct line, adjust the size, and confirm.
Flatten & Save
Our server flattens the signature into the PDF structure so it cannot be removed, rendering a ready-to-use document.
Secure Signature Flattening Engine
Why are basic online signatures insecure? Many websites only place a floating image overlay on the PDF, which can easily be removed by PDF editor software.
ZenPDF employs an advanced document flattening engine. When you place and confirm your signature, our backend burns the signature path directly into the PDF content stream as a vector path or flattened graphical object. This merges the signature into the document architecture, preventing removal and securing your agreement.
Draw, Type, or Upload
Complete signature flexibility: draw with a mouse/stylus, type using cursive fonts, or upload a scanned image.
Document Flattening
Embeds the signature directly into the PDF structure, ensuring security and print compatibility.
Multi-page Signing
Scroll through multi-page contracts, placing signatures or initials on every required line.
Strict Data Privacy
Conversions occur in isolated memory containers. Files are deleted in 60 minutes with zero exceptions.
The Benefits of Choosing ZenPDF
Why thousands of users trust ZenPDF every day for their document needs.
Fast Signing
Load your PDF and apply signatures immediately within seconds.
Encrypted Transport
SSL endpoints encrypt every upload, protecting contracts and private signatures.
No Installation
Draw and apply signatures directly inside modern browsers on any device.
Premium Account
Upgrade to sign larger files (up to 100MB) with priority processing.
Frequently Asked Questions
Ready to sign your document?
Join thousands of users who sign documents cleanly, securely, and without installation.