Which is correct? My bestfriend's name is Joanne. She is tall and big. She is friendly and I like her. or was it also correct to say...My bestfriend's name was Joanne. She was tall and big. She was friendly and I liked her.
If Joanne is still your best friend now, and you are talking/writing about the present, use the present tense.
If she is no longer your friend, or she is no longer alive, or you are talking/writing about a past episode in your life (like childhood) then use the past simple tense.