How to be polite?

greetings to everyone, I am a new member
If I may ask, what should I say to sound very polite if I am serving someone a cup of coffe or tea, the only phrase that I know is ‘here you go’ but doesn’t sound very polite to me


Perhaps you could say: May I/Can I offer you a cup of tea?


thank you for the replay,
I probably didn’t ask properly,

I am wondering what to say after the above mentioned question and positive answer from the person
I am talking about the moment when I am putting the cup of coffe on the table in front of that person;
what should I say, is ‘Here is your coffe sir’ polite enough?
sorry to bother you again



Yes, that’s fine