Like the GIF (that's Graphics Interchange Format), the PDF (Portable Document Format) has survived and flourished through the digital age. That's partly because of its versatility: It's the go-to ...

Smallpdf is a solid online PDF editor for making basic changes to documents on the fly. Smallpdf is a free online PDF editor that offers a limited but useful set of editing and conversion tools.

Gimp is normally used to create or manipulate images files, but can also work with PDFs if you understand how it works and what it's limits are. If you’ve never used Gimp—a free image editor available ...