The memory mirrors are part of the wiring from a Power Memory Seat, there are wires going from the Seat to the mirrors both L + R
If you are looking to do a Power Folding mirror retrofit its a bit more complicated, you have to replace your Mirror Boards and add new wires to the existing harness
As far as adding just electric mirrors, shoudn't be to hard at all, it will require some parts thought such as either do a direct wire replacement from a car with electronic mirror, or just add the necessary wires
There are only few wires for the electric mirrors, others are empty because no Memory Mirrors