This is a pretty general question and I wasn’t sure which forum to put it on so here this goes. I got quite a bit of AP credit but want to get a good GPA in college, it’s a bit vain I know, but can I re-take that class in college? What is the procedure for that? again just generally speaking, i’m sure different colleges have their own rules but the colleges i’m looking at don’t clearly delineate that on their website.
Yes, it’s (almost always?) possible! I’m retaking the intro chem courses and retook Calc 1. Always good to have a solid foundation. Plus, GPA boost. 
Yes, many people do. In fact my daughter’s AP chem HS teacher told her to re-take Chem 1 in college before taking advanced level chem courses as 1) she felt a college course would cover more ground and 2) she said each college emphasizes different areas – my D found both of these comments to be correct and was glad she took it again in college before moving on to the upper level chem classes there.
I wouldn’t retake it just for a good gpa.
Yes. Of course, you forfeit the AP credit.
Ask your advisor which classes you should re-take, and which you should get credit for instead.
If you report the AP credit to some schools (like the UC system) they give you credit for the class and you can’t later ask them to ignore it.
I’ve talked to people who received credit for the course (say Calc or chem) but chose to take the course so they could HAVE that background in college and that course on their transcript.
Policies vary. In the UCs, some allow you to retake (but your AP credit will then be erased), while others do not allow retakes.
If you have the option to skip or retake and intend to take more advanced courses that need that course as a prerequisite, try the college’s old final exams to check your knowledge.
Note that you are not necessarily assured of an “easy A” if you take a course that duplicates your AP credit. Some students doing that slack off “because they know the material” and end up doing less well than they thought (effectively wasting one of their 32 or so courses and not even getting as good a grade as desired).