Encrypting email must be one of the few things we really should be doing yet aren’t. I’ve worked in IT for over 13 years and only once has someone offered me a public key.
This Life Hacker article gets you up to speed really quickly, in fact
Mailvelope for Chrome or Firefox, and a webmail account like Gmail, Outlook, Yahoo, or GMX
might be all you need to read to get started!
I use K9 Mail on my phone, and Cryptography is enabled once you install APG – it’s a bit of a faff using IO File manager to read in keys from files as it’s not writing the path in the dialogue correctly… I have found it works seamlessly using dropbox though, just click on file and open with APG!
What’s the difference between signing and encrypting? This explains it well.