Up until the very early 1990s, computer keyboards had a place to position a cardboard (or sometimes plastic) strip, documenting the meaning of the function keys.
The computer (or OS) might come with one, but commercial software would also include a cardboard strip in the box, along with the manuals.
Many examples: https://www.getrevue.co/profile/shift-happens/issues/as-clos...
It's like upvoting is not enough, here. I've witnessed that some users love their Macbooks' Touchbars, at the same time I'm surprised so few users recourse to these extremely low tech tricks. Just like the camera cover thing that's also trending on HN best: pen and paper and other thing just (almost) anyone can use can still benefit proper use of rocket tech :)
edit: Plus thanks for the link! I've not read the article but the pics are great up to the end! So much inventivity on how to upgrade bona fide keyboards with relatively low tech all through computer history!
We have "Print Screen", which is a function I don't use that often.
(Not a Mac user, so I'm talking about regular PC keyboards).
In the old days I had a Sun workstation with Copy and Paste keys.