I just submitted my UCAS application, should I send my AP and SAT scores now?
You mean from CollegeBoard? no need until you get a request from a university.
No, I am an international student applying to UK schools through UCAS, should I go ahead and send my scores or do they request them?
Same answer, just different official source. Your predicted or achieved scores are part of your application. Any university that makes you an offer will specify the terms of that offer (which will be based on your predictions). You will be asked to document that you have achieved the scores specified in your offer. Once you pick what university you are going to firm (and insure, if it’s. a conditional offer) then you organize the sending of official score reports.
Okay thank you!