Most people who sign documents online fall into one of a few categories: they need to sign something a colleague sent, they need to sign a contract as a freelancer, or they're in a business that processes lots of documents. The right tool is different in each case.

Method 1: Mac's Preview App (Free, No Upload Required)

If you're on a Mac, Preview is the fastest and most private option, your document never leaves your computer.

  1. Open the PDF in Preview
  2. Open Markup toolbar (⇧⌘A)
  3. Click the Signature icon → Create Signature (trackpad or webcam)
  4. Drag the signature onto the document
  5. Save

Works for: any PDF. Free, instant, no account. See the full Mac signing guide for details.

Method 2: iPhone's Markup Tool (Free, Built-In)

Your iPhone has had PDF signing built in since iOS 11. Open a PDF in Mail or Files, tap the Markup icon, tap + → Signature. See the iPhone PDF signing guide.

Works for: PDFs received by email or saved in Files/iCloud. Free, no app download.

Method 3: Adobe Acrobat Reader (Free Version)

Adobe Acrobat Reader is free and handles both Windows and Android, which covers the gap left by Preview (Mac-only) and iOS Markup.

  1. Download Adobe Acrobat Reader free from adobe.com
  2. Open your PDF
  3. Click Fill & Sign → Sign yourself → Add Signature
  4. Draw or type your signature, place it on the document
  5. Save

Works for: Windows, Mac, Android, iOS. Free for the basic signing feature. The paid upgrade (Acrobat Standard/Pro) adds features like requesting signatures from others, which you don't need for personal use.

Method 4: Smallpdf or iLovePDF (Browser-Based)

When you can't install software, shared computer, work machine with restricted permissions, library, browser-based tools are your best bet.

  • Smallpdf.com → eSign PDF → upload → draw or type signature → download. Free for 2 tasks per day.
  • iLovePDF.com → Sign PDF → similar workflow. Free tier available.

Privacy consideration: Both services upload your document to their servers for processing. For sensitive documents (financial, legal, medical), use a local tool like Preview or Acrobat Reader instead.

Method 5: Create a Signature PNG and Insert It

The most reusable approach: create a transparent PNG of your signature once, save it on your device, and insert it into any document as an image. This works for:

  • PDFs (via Adobe Acrobat's image insert, or Markup on iPhone)
  • Word documents (Insert → Picture)
  • Google Docs (Insert → Image)
  • Google Slides, PowerPoint, or any app that supports image insertion

Create your signature PNG for free at SignatureHub, draw it, adjust it, download as transparent PNG. Store it somewhere easy to find (Downloads folder, Desktop, or iCloud) and you're set for any document, forever.

When to Use a Paid E-Signature Service

The free methods above are fine for most everyday documents. Consider a paid service like DocuSign, Adobe Sign, or HelloSign when you need:

  • Others to sign, sending a contract out for signature and tracking whether they've signed it
  • Audit trail, legal proof of who signed, when, from which IP address
  • High-value contracts, real estate transactions, employment agreements, financial documents where signature verification might be challenged
  • Volume, if you're signing or sending dozens of documents per month, the workflow tools in paid platforms save significant time

For signing your own documents, a contract someone else sent you, a form, an agreement, the free methods work perfectly well for the vast majority of situations.

Quick comparison: For Mac users, Preview is the best option, fast, private, no upload. For Windows users, Adobe Acrobat Reader free is the equivalent. For anyone on a phone, iOS Markup (iPhone/iPad) or Acrobat Reader mobile is the right choice. Use browser tools only when you can't install software.

Create a Reusable Signature PNG

Draw or type your signature once, download the transparent PNG, and use it in any document on any platform.

Create Signature – Free