Free software on your phone or tablet lets you scan, create, edit, annotate and even sign digitized documents on the go.

You can digitally sign a PDF in several different ways, including Adobe Acrobat, Apple's Preview app, and mobile apps, among other options.

For some of us, our phone is our primary computer -- and that means printing the occasional document from your mobile device. Whether it's a spreadsheet or a travel itinerary, sometimes it's just ...