Mac genuinely does signing well. Preview's trackpad capture is one of those Apple features that feels like magic when you first try it. So why use anything else? Because sometimes signing isn't the only thing you need to do.
Preview's trackpad signature
Open the PDF in Preview. Click the markup toolbar (briefcase icon). Click the signature button (squiggle). Choose Trackpad, click Click Here to Begin, sign with your finger on the trackpad, hit any key when done. Drag the signature onto the page. Preview remembers it for next time.
For one-off signatures on documents that need nothing else, this is the fastest path on any Mac.
When Flint is better
Preview's signature has limits. It can't handle documents that need editing first — typing your address into a blank field, fixing a typo, adding a date inline. Mixed signing-and-editing jobs go faster in Flint: edit text, drop signature, download, done. One pass instead of bouncing between Preview and another tool.
Camera signature
Preview also lets you sign on white paper and hold it to your Mac's camera. Preview captures the signature, cleans it up, and stores it. Result is usually crisp and looks exactly like your real signature. Useful one-time setup; then use the saved signature in either Preview or Flint going forward.
Multi-signer documents
If multiple people need to sign — a partnership agreement, multi-party contract — pass the PDF around digitally. Each signer adds theirs in Preview or Flint, saves, sends to the next. For larger workflows (5+ signers, audit trail), a dedicated e-sign service handles routing better; for everyday cases, browser plus email is enough.
FAQ
Is Preview's signature legally binding?
Yes, under e-signature laws (eIDAS in EU/UK, ESIGN in US). A clear intent to sign plus a reproducible mark generally counts. For high-assurance signing (deeds, notarisation), check local requirements — qualified e-signature services may be needed.
Can I use the same signature in Flint as in Preview?
Each tool stores its own signature. Set them up separately — takes thirty seconds each. Or sign on paper, scan, and use the same scan as image in both. Result is identical.
What if I'm using a desktop Mac with no trackpad?
Camera signature works on any Mac with a webcam (which is all of them). Sign on paper, hold to camera, save. Or in Flint, use the mouse to draw the signature — looks less natural than trackpad but functional.
Preview for quick signs, Flint for sign-plus-edit jobs. Pick by what else you need.