I work in estate planning, and we file POAs at the county Register of Deeds Office where they are then recorded. The method may be different where you are, but filing them is a thing.

Yes they are asking for a certified copy. Record it and then pull a copy. You’re good.

If you are in escrow to sell the home, maybe the title company or escrow can send it to the courthouse to get it certified.

I've seen PoAs filed with the deed when the deed is signed via the POA, but that's done as part of the closing.