In person and in-person are both correct, but they are used differently.
In person is a phrase. It means someone is physically present. It usually comes after the verb.
- We met in person.
- She prefers to talk in person.
In-person is an adjective. It describes a noun, so it usually comes before that noun.
- We had an in-person meeting.
- The class includes in-person sessions.
A simple way to choose is this: if the words describe how something happened, use in person. If the words describe a noun like meeting, class, or event, use in-person.
Compare these: We interviewed her in person. It was an in-person interview. Same idea, different grammar job.
