To argue in favour of something, to support and justify. So, you give all the reasons why something should be done.

It means to explain why something should be done or why something is the best (ex: "My husband keeps making a case for buying a new car"). Hope this helps!

No. The meaning is different. google what is the meaning of make a case for https://dictionary.cambridge.org/dictionary/english/make-a-case-for-sth

An action in a court of law is "a case." A lawyer who argues for a certain legal point "makes a case for" the point. In everyday speech, it means "to put together facts and logic to support an argument." "OK, I agree that installing solar panels will be good for the environment. But you haven't made the case that it is actually going to save me money." "We usually think of Stephen King as a slick, commercial writer of entertaining bestsellers. But a recent article in the New York Review of Books makes the case that his books have a real place in American literature." "Cell phones a triumph of technology. But you can make a case that they have done the world more harm than good."

wait, no. I think you can say 'who are you making this for?' or 'what are you making this about?'