Do you know what must an introduction have? Please help me!=]

Question

Introduction to what?

Just a introduction. Whats like the most important thing that it needs to have. That main thing.

A topic sentence?

Like is it the body ,tittle ,or something else?:`

This is a pretty vague question. If I had to choose, the topic (thesis) sentence would be the most important, after all, this is the introduction the the main event, the body.

http://www2.hmc.edu/~alves/intros.html

Thanks! :]