A tag question is a special construction in English. It is a statement followed by a mini-question. The whole sentence is a "tag question", and the mini-question at the end is called a "question tag". We use tag questions at the end of statements to ask for confirmation.
You’ll write to me, won’t you?
I’m dressed smatrly enough, aren’t I?
We’ve been invited, haven’t we?
You’ve got enough, haven’t you?