The old workflow of printing a PDF, signing it by hand, and scanning it back is wasteful and slow. With modern browser technology, you can sign any PDF document in seconds, directly in your browser, with no printing, no scanning, and no software installation required.
This guide explains the different types of PDF signatures, when each applies, and how to add your signature to a PDF for free.
Types of PDF Signatures
Understanding the difference between signature types helps you choose the right approach for your situation.
1. Image-Based Signature (Most Common)
You draw, type, or upload a signature image that is placed as a visual overlay on the PDF page. This is what most free signature tools offer. It creates a visual representation of your signature.
Best for: Internal approvals, agreements with people you know, personal documents, and any situation where the visual signature is sufficient.
Limitation: This type of signature does not cryptographically verify your identity. Anyone could draw the same signature.
2. Digital Signature (Cryptographic)
A cryptographic signature binds your identity, verified by a Certificate Authority, to the document. The PDF records a mathematical fingerprint of the document at signing time. If anyone changes even one character after signing, the signature becomes invalid.
Best for: Legal contracts with high liability, government documents, regulated industries.
Limitation: Requires a digital certificate issued by a Certificate Authority, which typically costs money. Not needed for everyday use.
3. Electronic Signature Platform (DocuSign, Adobe Sign, etc.)
Cloud-based platforms add audit trails, timestamping, and email confirmation. They are essentially image-based signatures with a service layer that provides legal evidence of who signed and when.
Best for: Contracts with external parties where an audit trail matters.
Cost: Usually subscription-based.
For the vast majority of everyday signing, employment forms, NDAs, rental agreements, consent forms, parental permission slips, an image-based signature is entirely sufficient and legally recognized in most jurisdictions.
Step-by-Step: Sign a PDF in Your Browser
LocalPDF Sign lets you add a signature to any PDF entirely in your browser, with zero uploads.
Step 1: Open the Sign tool Go to uselocalpdf.com/tools/sign.
Step 2: Upload your PDF Click to select your PDF or drag it onto the upload area.
Step 3: Create your signature You have three options:
- Draw: Use your mouse or touchpad to draw your signature on a canvas pad
- Type: Enter your name and choose a handwriting-style font
- Upload: Upload an image of your existing signature (PNG with transparent background works best)
Step 4: Position the signature Click on the page where you want the signature to appear. Drag to reposition it. Use the resize handles to scale it to the right size.
Step 5: Download the signed PDF Click Save. The signed PDF downloads to your device with the signature embedded as a permanent visual element.
Tips for a Professional-Looking Signature
Use a transparent background. If uploading a signature image, use PNG with a transparent background so it blends naturally onto the document without a white box around it.
Match the scale to the document. A signature that is too large looks amateurish. Scale it to roughly the size of a handwritten signature, about 2-3 cm high.
Position precisely. Most signature lines in documents have a designated space. Zoom in to position the signature accurately on the line.
Sign in the right color. Traditionally, signatures in blue or black are standard. Avoid red or other colors unless the document specifically requires it.
What About Legal Validity?
In most countries, an electronic signature (image placed on a document) is legally valid for most purposes. The EU eIDAS Regulation, the US ESIGN Act, and UETA all recognize electronic signatures.
However, some document types explicitly require a wet (physical) signature or a certified digital signature. These include:
- Wills and testamentary documents
- Court documents in some jurisdictions
- Notarized documents
- Some government forms
If you are unsure whether your document requires a specific type of signature, consult a legal professional.
Privacy When Signing
Your signed PDF may contain sensitive personal and legal information. When you sign a PDF using a browser-based tool like LocalPDF, the document never leaves your device. The signing process, including your drawn or uploaded signature, happens entirely in JavaScript running in your browser tab.
Cloud-based signing platforms, by contrast, upload your document to their servers. This is usually fine for business purposes, but for highly personal documents, local processing offers additional privacy assurance.
Conclusion
Signing PDFs without printing is fast, environmentally friendly, and just as legally valid as a hand-signed document in most situations. Draw your signature, position it on the page, and download, the whole process takes under a minute with a free browser-based tool.