Section 31. In addition to the forms expressly required by any other provision of law to be as prescribed or approved by the commissioner, the commissioner may prescribe any other form considered necessary or convenient for use under any provision of chapters 59 to 65C, inclusive; provided, that variance from a prescribed form shall not affect the validity of the form so used, if the form used is in substantial conformity to that so prescribed. In any case where the commissioner prescribes a form, the form may be completed or maintained electronically.