Phil went to a movie with his friends is a form of active or passive?

Active.

Phil went to a movie with his friends.

Phil is the subject

went to is the verb

a movie is the object

Active voice is subject + verb + object

Passive voice is object + verb to be + verb (past participle) + subject

The sentence in passive voice:

A movie was gone to by Phil and his friends.

A movie is the object

was gone to is the verb

Phil and his friends is the subject

However, people are usually more important so they should be mentioned first.