I bet you never noticed. I didn’t. Your keyboard has tiny hyphen-shaped bumps molded on the bottom of your F and J keys. They are to help position your fingers properly by feel, without having to look down. But I can barely feel them.
On the numeric keyboard, on the far right of many computer keyboards, the center 5 key also has a bump. Why didn’t someone tell me this before? (Wouldn’t have helped me, anyway.)
The bumps are probably on an old typewriter keyboard, too, but I no longer have one to check, not even in the dark corners of my attic.
A computer keyboard also has F-keys, numbered 1 through 12, at the very top. These are the Function Keys and are defined by the software. Often, they do nothing. The F1 key, by custom, often brings up a help menu.
On my very first experience with my company’s IBM computer back in the 1960s, these were actual switches on the computer that were set by the operator before running a program. For example, F1 on could mean sort the data alphabetically, F2 could mean use the format with the name first. They saved the need for writing a separate program for each minor difference.