Q: Would you please tell me what macros are please?
A: A macro is anything more than a single command. For example, in AutoCAD you zoom into a windowed area with the ZOOM command, followed by the W option. When you assign that to a menu item or a toolbar button, "zoom w" is called a macro.
A macro can consist of just a command and an option, as shown above, or consist of many commands, their options, and other programming code (AutoCAD macros can include Diesel expressions and AutoLISP functions).
Macros often include additional code to make sure it works under all conditions. For example, "^C^C^C" is added as a prefix to cancel any AutoCAD command still running, while the _ (underscore) is added to ensure the macro works with any language version of AutoCAD (German, Japanese, and so on).
Programs other than AutoCAD don't necessarily allow macros; instead, they have their own programming interfaces, or might require you to learn VBA (Visual Basic for Applications) to write the equivalent of macros.