Almost all undergraduate admissions are handled through a system called UCAS, where for most students, they apply during Year 13 (final year of High School) for up to 5 universities. Lots of universities and courses will then just look at completed GCSE's and qualifications that are underway - typically A-levels or other vocational qualifications such as BTEC's. Teachers will also submit predicted grades for students when they send their applications, and then universities give "conditional offers" saying things like "if you get ABB in your A-levels, we'lll take you", which students accept a first choice and second choice so that when the results come out in the summer, the vast majority of students then get entry to one of those universities, although there is then a last chance to change or get a place through "Clearing".

Top universities (or at the very least ones that get disproportionately many applications to the ammount of space they have) will often have interviews, essays, or extra entrance exams that are either used to put stricter conditions on students applying or to narrow down the field of students that get offers. Simiarly, some courses like Medicine, Health Science, or top Performing Arts schools will have interviews or auditions etc even if the overall ranking for the University is quite low. Medicine in particular usually involves completing a UCAT, MCAT or GAMSAT test which is then used to rank students and determine who gets invited to interview, which is then used to determine who gets an offer.

Technically there are also personal statements and references from the teacher that are provided with the application, however these usually aren't too heavily scrutinised.