How to Sign a PDF Document on Android Unlike an iPhone or iPad, the default file manager that comes pre-installed with most Android skins doesn’t offer a built-in PDF signing feature.

This detailed guide covers how to sign documents on iPhone and iPad without needing a third-party app or service.

Sign with Google Drive on Android or iPhone The Google Drive app -- included on all Android phones and can be downloaded onto an iPhone -- includes markup tools that make it easy to sign a document.

Chances are you've had to use your computer to digitally sign a document at some point in your life, whether through a service like DocuSign or a brief back-and-forth with a PDF document. However ...