The female equivalent of Ambassador is Ambassadress.
An ambassadress is a female ambassador.
In English there are no masculine or feminine forms. English uses gender specific nouns for male or female.The noun 'ambassador' is a common gender noun, a word for a male or a female.
Ambassador may be either male or female. (The term ambassadress is not used!)
An Ambassador's office is called an Embassy.
I believe you are thinking of an ambassador.
An ambassadrix is another word for an ambassadress - a female ambassador.
We call a representative to a foreign country an ambassador.
Frances E. Willis, the first female full ambassador, was first appointed as a field service officer to Switzerland in 1953 by President Dwight Eisenhower. John F. Kennedy was President when she reached the rank of full ambassador (to Ceylon) in 1962. The question is too vague to say definitively whether DDE or JFK was the one who appointed her as the first female ambassador -- DDE first appointed her, but she wasn't a full ambassador until nine years later under JFK.
Embassy
In 1923, Alexandra Mikhailovna Kollontai was appointed Soviet Ambassador to Norway, becoming the world's first female ambassador. Later she served as Ambassador to Mexico (1926) and Sweden. She was also a member of the Soviet delegation to the League of Nations.
An ambassador