My DS was diagnosed with Asperger’s at age 5, he’s now at university. Nowadays he would have the label ASD (like his much younger sibling), very academically bright and “high functioning” but as you know, that certainly doesn’t mean no problems.
He did declare his diagnosis on his UCAS form, but I know that many others don’t, because when my other 2 DC (neurotypical) accepted their Uni offers, both got standard emails asking them to please declare any issues such as ASD, dyslexia, etc, any other issues so that they could be assessed.
My DC did provide information from his school and Dr, and also was interviewed, had some assessments, I think it was student disability services that did it (not really sure of the name, but it was organised by the Uni and carried out on campus).
He continues to get the extra time in exams (on computer where appropriate), that he got in school.
In 1st year he had a mentor, and he can go and ask for help with organisational stuff. He was also awarded money for a laptop and some other stuff.
I was in the first assessment meeting he had the summer before he started Uni (at his request), and from that, I can tell you he would have also got money for taxis to and from Uni, if he had been incapable of using public transport (mostly because where we live, there’s very little public transport, it’s rural, most people go by car)... in his case, although he was quite anxious about using public transport, we had devised our own plan and over the summer he spent time traveling around on busses and trains (we scenario- planned, “if you miss the bus then...”etc etc).
So yes, there is a lot of help, but the young person has to be quite proactive in asking for it, and discussing their needs... so please prepare your DC for that aspect!