I need a certified copy of my DC state tax return

[xmasbaby0]

There is no such thing as a "certified" copy of your tax return.  TurboTax provides software for a self-prepared tax return.  You can print a copy of your return for yourself.

https://ttlc.intuit.com/community/prior-year-return/help/how-do-i-get-a-copy-of-a-return-i-filed-thi...

[fanfare]

you certify the return by signing it and submitting it to your lender or other interested party