Comment vas mon amie

"comment VA ?" is a shortened form of "comment ça VA ?"

the writing "comment vas ?" could also be a shortened form of "comment vas-tu ?"

Both shortened forms indicate a somewhat sloppy use of language while the non-shortened forms are familiar but correct.

"mon ami" is my friend (gender masculine), mon amie is a female friend.

"comment vas-tu mon amie ?" could be translated as "how are you my friend"