Ask HN: What "obvious" computer things might your mother not know?

While recently providing technical support to my mother (66) who has worked in an office environment from 1998 to 2018 I discovered that she did not know that resizing a window was on option (she knew about maximize and minimize).

I'm now thinking that there are likely a whole category of, to me, "obvious" things that she doesn't know that might be helpful for her to know.