Shortcut keys to simulate clicking the Save or OK button

I am an old keyboard freak, wrote about how to use win explorer ONLY with keys many years ago - downloaded some mio of times.
I never liked using the mouse too much. Maybe this my wish needs a general change of windows, but I would like to hit keys (like Ctrl+Enter) to Save or finish a task in admin to avoid moving the mouse typically in upper right corner of a 27'' monitor to hit a Save or OK button