7 - Do I have to mail anything to the Comptroller's Office if I file my Maryland return electronically?
Electronic filing is essentially a paperless function. But there are certain tax credits that require you to submit supporting documentation with your signature document Form EL101. See Tax Credit Certification for Electronic Filings. In addition, if you plan to file a Form 502 or Form 505 electronically and pay any balance due with a check or money order, you must complete Form IND PV (Electronic Income Tax Payment Voucher) and send it to us, along with your payment. You do not need to use Form IND PV if you are making a direct debit or credit card payment. For more information, see Necessary Paper Forms for Online Filers