From what I've read, when introducing characters for the first time you are not supposed to give their name until the point in the screenplay where they introduce themselves or something in the story gives us their name.
From what I understand, the first action a movie shouldn't be something like "Mike walks into a dark office" because we don't know who Mike is yet. So if he gets into a conversation in the beginning of a script before we know who he is, his name should not be included when writing dialogue at this time.
But if it starts out something like "A man walks into an office and turns on a light. On the desk is a name plate with the name Mike Smith. He sits in the chair behind the desk and picks up a picture of what looks like a family. There are two young children, a woman and him..." So now if he gets into a conversation now his name can be used because we established that he is in fact Mike.
Sorry if this is a stupid question but the more I read, the more conflictinn information I get
Thanks