Please give credible sources so we can know for sure.
更新1:
Here is one sources that explains write-ins need to be registered. https://ballotpedia.org/Ballot_access_for_presidential_candidates "An individual can run as a write-in candidate. In 35 states, a write-in candidate must file some paperwork in advance of the election. In seven states, write-in voting for presidential candidates is not permitted. The remaining states do not require write-in candidates to file paperwork in advance of the election."
更新2:
Please remember to include if Bernie Sanders is registered. That's the main part of the question.
