Macro in excel - what is it?

If someone sends you a macro file and it won't run, that's usually excel blocking it on purpose - macros in files from email or the internet are switched off by default. Right-click the file, properties, tick Unblock at the bottom, reopen. And save your own as .xlsm, because a normal .xlsx drops the macros when you save.

A macro is just a recorded sequence of clicks you can replay - handy when you do the same formatting or the same cleanup every week. The web version matters a lot here though: it won't record or run the old VBA macros at all. You can open a file containing them, they just sit there dead. What the browser version has instead is Office Scripts, which does a similar job but only turns up on a work or school account, not a personal one.