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

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

Scanner puts a full scanning and PDF toolset on your iPhone, iPad, or Android device. Create high-quality scans, run OCR, ...

Make a digital copy of your deeds and titles, save other important documents, and turn tax paperwork into PDFs with the best scanning apps ... where I edited articles on topics such as cameras, ...