Most freelance jobs go wrong in the same place: the brief arrives as four messages across three days, nobody writes down what was agreed, and the extras arrive later as if they were always included.
Paste the client message in. You get one page back: what is in, what is out, the fee, the deposit, and a line for them to sign. One page, because a page they will actually read beats a contract they will not.
$19 CAD, one time. You can run it in the browser before you buy.
Not a law firm. Not legal advice.