I would like to know how long Bibi Fatemah (as)
owned Fadaq during the Holy Prophet's lifetime?

After the victory of Khayber when Holy Prophet (saw) has received the Fadaq. This ayah has revealed:
????? ??? ??????????? ??????? ?????????????? ??????? ?????????? ????? ????????? ??????????

And give to the near of kin his due and (to) the needy and the wayfarer, and do not squander wastefully.(17:26)
Then Holy Prophet called Hazrat Fatima Zahra (s.a) and gifted the the whole land of Fadaq which remained with her for around 4 years.