Excel

Hi Natalia, thank you for your post, welcome to the forum, in answer to your question:
The writing/editing and using of macros is covered comprehensively in our Excel Advanced and Excel VBA courses.
But to answer your question; a macro is a recording of mouse clicks and/or of keyboard entries which are recorded by Excel and played back (like a tape recording) whenever required, a macro is usually recorded to undertake mundane or repetitive tasks.
These tasks can be simple or complex, Excel will undertake them on demand, I hope this has helped, if so please click the Resolved link, best regards Pete.