From time to time, you will find yourself performing a sequence of menu commands over and over. You can automate that sequence by creating a macro, which is simply a recording of those commands. Much like a tape-recorded message, you record the sequence of commands once. In the future, you simply "press play" and the commands are executed exactly as they were recorded. You can add macros to keystrokes, menus, or toolbars to make them more accessible.
Note that macros are not used as frequently as they were in older programs. Many of the tasks that were achieved by recording macros, particularly in older versions of Word and WordPerfect, are now features included in Word, such as AutoText, AutoCorrect, and Styles.
Macros have become useful for computer programmers and developers, who can write (not record) macros in Visual Basic, a programming language. These complex macros can perform extraordinary tasks for customization and automation of office processes. As a user, you will not generally program Visual Basic macros.
You may record a macro from time to time, however. For example, you might record a macro that performs a shrink-to-fit operation. Or you might record a macro that sets the printer to the fax software, faxes your worksheet, then sets the printer back to your normal printer. Notice these are strings of simple commands. Such are candidates for a macro.