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

PDF Expert is fast, intuitive, and complete, giving you everything you need to make document management simple and efficient.

There’s a plethora of services which do this, including Wondershare’s (mostly free) HiPDF. This review focuses on Wondershare's online service, but a desktop app, PDFElement, is available.

Controlled by Lei Jun, one of China's most prominent entrepreneurs and head of smartphone giant Xiaomi (1810.HK), Kingsoft is ...