Access to medicineWatch
Firstly, research the universities you want to apply to because only around half of med schools (or less) even accept Access courses. On top of that, some are picky about where you did the course. I did mine at City and Islington. Other good ones are Lambeth, Manchester, Sussex Downs, CoWA (this is the most accepted I believe) and some others.
You can't do them online although they are mostly online right now because of Covid. There may be distance learning ones but I'd be wary, given what I said about Med schools being quite selective about where you take the access course.
You will likely need Bs in GCSE Maths and English Language (most med schools require this at the very least) and they will require you to have taken the UCAT/BMAT. My college required a minimum 630 UCAT score in order for them to support a Med or Dentistry application.