write in candidate and the electoral college

How does one vote for a write in candidate with the electoral college system? Do they put down ‘electors for (write in candidate)’?

Also can a person cast a ‘write in a vote’ for a write in elector by name as in John Smith as elector, without specifying a candidate?

It depends on the state. In Ohio, write-in candidates have to register their elector-candidates. ETA: Here’s the form.