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 electronically and pay any balance due with a check or money order, you must complete Form EL102 (Electronic Income Tax Payment Voucher) and send it to us, along with your payment. You do not need to use Form EL102 if you are making a direct debit or credit card payment. For more information, see Necessary Paper Forms for Online Filers