Adobe Acrobat has been the default association with PDFs for so long that many people assume you need it to sign one. You don't. Whether you're on Windows, Mac, iPhone, or Android — and whether or not Adobe Reader is installed — there are four straightforward ways to sign a PDF without touching Acrobat.

Option 1: Use an online signing tool

A browser-based signing tool is the fastest, most portable option. There's nothing to install, and it works the same on every device. With eSign Services, you can upload a PDF, apply your signature, and download the signed copy in about a minute — no account required.

Online signatures are legally binding under the U.S. ESIGN Act and UETA, provided the platform captures intent, consent, and an audit trail. eSign Services embeds all three into every signed document.

Option 2: Mac Preview

If you're on a Mac, you already have a signature tool. Open the PDF in Preview, click the Markup toolbar, and choose the signature icon. Capture your signature with the trackpad or your iPhone camera, then drag it onto the page.

It's free and offline — good for personal use, but it doesn't produce a formal audit certificate.

Option 3: iPhone / iPad Markup

iOS handles PDFs natively. Open one from Mail, Messages, or Files, tap the Markup icon (a pen tip inside a circle), then choose the signature tool. Sign with your finger or Apple Pencil, drag the signature into place, and share the signed file back.

Android has similar functionality through the built-in Drive / PDF viewer or apps like Xodo, though the exact steps vary by manufacturer.

Option 4: Google Drive + Google Docs

In a pinch, you can open a PDF through Google Docs, insert an image of your signature, and re-export as PDF. It works — but formatting often shifts, tables break, and the result won't include a signing certificate. Use this as a last resort, not a standard workflow.

Which option is best?

It depends on what you need the signed document to do.

  • Signing a personal document for yourself? Mac Preview or iOS Markup are fine.
  • Signing a contract you'll send back to a business? Use an online tool that generates an audit certificate — like eSign Services. Businesses increasingly expect that certificate, and it protects you if a dispute ever comes up.
  • Signing something legally sensitive? Always use a tool that produces a tamper-evident audit trail.

For a deeper comparison of every method — including Adobe Reader — see our full guide to electronically signing a PDF. Or, if you're ready to sign now, try eSign Services and skip the software entirely.