As far as i know the applications for universities close somewhere in January/February, and A-level results will only be released in August. So how are the A-level results applicable during application period? I'm rather confused by how the whole thing works.
Or do they use A-level predictions to apply for university?
GCSEs+ AS results + A2 predictions - your offer is based on you actually getting the required set of grades at A2.
Some universities will also require you to sit additional entrance exams, most of which are done in the September to December period.
Most subjects require an application to be submitted by January I believe apart from Medicine, Dentistry, Veterinary and Oxbridge applications which need to be submitted by October.
UK students will use their GCSE results, AS results and A2 predictions (from the school and previous GCSE and AS results are used to make these) in terms of results.
Universities will make either a conditional offer (e.g. student must achieve A*AA to be accepted into the course) or an unconditional offer (doesn't matter what you achieve at A level). If you miss your A2 grades on results day (e.g. get A*AB) you either go into clearing or see if your university will take you anyway - leniency varies depending on course and institution.
UK students will also submit a personal statement which they write themselves talking about things like why they feel they should study said course as well as extra curricular activities. Furthermore, a reference is submitted which is written by the school to the university.