You would say the official uniform or the company/bank/school uniform

Hi Alice, It was great to read your answer. I think it is the adjective that I need. If they are not used much, what would British say instead? Anyway i will use pre -determined, thinking it is the most suitable. thank you very much Any question about Spanish? Glad to help you

Maybe you could say "pre-selected" or "pre-determined". Pre-selected is more if the person picked out the clothes themselves ahead of time, pre-determined might be if there was a rule or something that forced them to dress a certain way. But these are not very common expressions to use. "She was able to get ready for the party quickly, because she had pre-selected which dress to wear." "He looked at the clothes in his closet, seeing a row of identical white shirts and black pants. It was pre-determined what he would wear from Monday through Friday."

thanks a lot Steve. maybe there is no such adjective¡¡

I'm not really aware of an adjective, but you could say something like "the clothes I have hung out for tomorrow".