On-screen instruction regarding the use of a program. There is typically a Help menu in today's operating systems and applications. On Windows PCs, pressing F1 is the de facto standard for getting help. On the Mac, Help is an option in the Finder menu.
A One-Line Standard Is Woefully Lacking
There are tons of articles and videos on the Web for helping people use their operating systems and applications. If users are lucky, the help they read pertains to the software version they have. Unfortunately, instead of the first line of help indicating which software version the help is for, there is often no reference to version numbers at all. Menus and tabs in software are constantly changing from version to version, and people waste a lot of time following a set of steps only to find that half way through, the software has no resemblance to the help because it is a previous or subsequent version. See
context sensitive help and
online help.