A Nisus Writer Macro is a list of instructions that runs from top to bottom. All normal menus, such as Format > Bold, are macro commands that do exactly as their menu counterparts. A macro can be as simple as:

Bold

Display As UPPERCASE

That macro would make all selected text appear as if the bold and uppercasing menus had been activated. If a menu name is ambiguous, you can use a menu path to differentiate them:

Text Color:White

Background Color:Gray

That macro would color all selected text to appear as white text on a gray background. 

Much more complicated macros are possible using the commands and features described in this document.