Vim is very customizable. You can adjust key-bindings to your liking.

For example, if you want to save a file, you’ll type :w or :up in command mode.

But maybe you’re used to press CTRL+S to save a file?

You could add a custom key-mapping to your configuration file (~/.vimrc or similar):

nnoremap <silent><c-s> :<c-u>update<cr>

The command works in normal mode.

You can also bind CRL+S for other modes (visual mode and insert mode):

vnoremap <silent><c-s> <c-c>:update<cr>gv
inoremap <silent><c-s> <c-o>:update<cr>

The gv in the key-binding for visual mode preserves your visual selection.

You must disable how your terminal interprets CTRL+S. For example, I added the following line to my ~/.bashrc:

stty -ixon

Further Reading