uploading GCSE and A levels certificates

Should you get an email from UCAS telling you to upload proof of your grades? My friend said she got it but I haven't had anything. Or is this after you get an offer?

Never heard of this. If you're applying in year 13 via your school, as most people do, then the process is automated and you don't have to do a thing. If you're applying during your gap year, then the universities will most likely ask for proof of your grades. When I applied during my gap year, the universities that gave me offers all requested copies of my certificate, but always via their own admissions portal and outside of UCAS

Did they ask for you gcse(or equivalent) as well, or for A levels only?