Return filing requirements: prescribed form, verification, supporting documents and separate returns for agents and trustees. Every return must be furnished in the prescribed form and manner, contain required particulars, be signed and verified by the appropriate person, and be accompanied by all documents specified; if no form is prescribed a written return may be served on the Commissioner who may require re-submission in a specified form or manner; agents and trustees must furnish separate returns for principals or trusts where required, and a prior provision on mandatory electronic filing for notified dealers has been omitted while the Commissioner retains filing-direction powers.