Bom dia!
What is the correct way to ask if you can provide your NIF when someone doesn’t ask?
I usually say, “Posso dar-se o meu contribuente?” and that works, but sometimes I have to repeat myself and I don’t know if that’s because of 1) my accent, 2) not the best way of phrasing it, or 3) both.
Obrigada!
Olá, @evolmer! Your sentence sounds fine, needing just small corrections. It should be ”Posso dar o meu contribuinte?” . You can also phrase it as ”Posso dar o meu NIF?”, “Pode acrescentar o NIF?” or even something as short as ”Pode pôr o NIF?”, which might be easier to pronounce. Everybody understands NIF, so you can save yourself some trouble and avoid the big word contribuinte if it helps 
Thank you so much! I really appreciate it.