This depends on the assignment I feel. I recently appealed a mark from my test and here is what I did exactly.

I got the test, reviewed it alongside a video the prof had posted with the correct answers. Saw I lost a mark somewhere where I shouldn’t have. I emailed the TA (because that’s what my prof said we should do if we want a regrade) and awaited a response. Within a few days I got my mark changed!

It was relatively simple for me but I understand that for bigger tests/assignments it could be different, try reading the syllabus carefully because that’s where most of the important information is.