Best way to tell a user what a form is for?

I'm designing a form, and my client hasn't made a FAQ or any type of documentation. Nor do they want me to make one right now. So, how can I tell a user what the form they're filling out is for?

The client currently tells the user what the form is for when they press the submit button (a modal pops up telling them what they're about to do and whether they accept or want to cancel), but they want to tell the user before they press the submit button. So, should I just straight up put a paragraph at the bottom of the form? Top? Any advice would be helpful. Thanks.