marcos are collections of frequently used commands which are grouped together in a file. Instead of entering commands individually, users can call the macro and the commands stored therein will be executed automatically.

An Anology would be eating out as opposed to cooking at home. Cooking for yourself at home is sans macros, cooking, preparing, laying the table. Going to a resteraunt is with macros, it's already done for you, all you need to do is order & eat.

EDIT: That is possibly the worst anology ever, I apologise unreservedly, I offer my sister as compensation.