Student can't log in to Zoom to change their name
Students do not have actual Zoom accounts. They can't sign in to Zoom. The only way for them to get on a Zoom call is via a link or a meeting ID that they type in.
If a student's name does not appear correctly, they can change it after they join a meeting by opening the participants section and clicking on their name and selecting Rename from the list that appears. (The default name listed is the name of their iPad.)