There are a bunch of different ways to write files, to quit out of a Vim session, and to write and quit.

The standard is :wq to write to the file and quit. There is :xall which will write changes to all buffers and quit.

:q, :q!, and ZQ—the latter being a normal mode command—are all ways of quitting Vim. The first will warn of unsaved changes. The other two will discard unsaved changes.

Another favorite of mine, when bailing on a git commit, is :cq.

These and more can be found in the help files by running :h Q_wq.