What do macro's do in excel?

You can record an action that you complete and then assign it to a button for example. Then each time you press the button it will complete that action. For example if i have lots of tabs in a sheet and i want to create a menu tab then i would record a macro and click onto the tab that i want to open. I'd then stop the macro. I would then create a button on the menu sheet and assign that macro to it. This would mean every time the button is click, that tab would open. You can use them to perform lots of different things in excel. So it records key strokes and actions. This is a macro in its simplest form. More advanced macros can do all sorts of things and usually require VBA code.