Hw did you all address ur supervisor- by first name basis or using the title like Dr or Prof? Recently, my supervisor asked to address her by first name. Is it ok? She is my phd supervisor

I am first on name terms with my supervisor. If they are happy for you to use their first name instead of calling them Dr then that is fine. However if for cultural reasons you would feel more comfortable addressing her as Dr then that is also fine, just politely explain this to her so that neither of you will feel awkward.

I address everyone in my department, including both my supervisors (one of whom being a Prof and Dean of the school!) by their first name, and we wouldn't have it any other way. Whilst they have (much) more experience in the field we treat each other as intellectual equals... I learn from them and, occasionally... they learn from me! lol :)