I long ago gave up using Gmail due to privacy concerns. Still, lots of folks—and companies—still use it because, among other things, it does have the advantage of portability that doesn’t depend on your current ISP or your OS. Gmail is easy to use as long as you use their Web UI.
If you’re an Emacs user who’d like to deal with email from within Emacs, however, things are bit more difficult. The hard part is retrieving mail from Gmail’s IMAP server. You’d think you could just use your usual credentials but that doesn’t work.
Jakub Kadlčík has a post that explains how to configure mbsync to deal with Gmail. The difficulties mostly involve generating and using a special password. I’d like to beat up on Google for making things so difficult but they’re simply trying to make the process a bit more secure and, truth by told, setting things up for Apple Mail is similar.
I’ve never configured mbsync for Gmail but I did for Apple Mail and found it difficult because I couldn’t find any write-ups on how to do it. As with Gmail, the difficulty is not the mbsync configuration file, it’s generating the special app password you use. It’s the same with Gmail: the tricky part is knowing that you need an app password and finding out how to get one. That’s where Kadlčík’s post comes in handy. If you’d like to retrieve Gmail with mbsync—or, really, any of the IMAP downloaders—take a look at his post.