If you’re asking about “faced” or “unfaced”, then there is no interior finish on the wall. Otherwise, you couldn’t install batts with the paper facing.
So, if you live in a climate where you are mostly “heating”, I’d use: 1) paper faced batt insulation on the heated side, 2) fasten the paper to the studs, 3) completely fill the stud space with insulation, (i.e.: 4” batts in 4” wall, 6” batts in 6” wall, etc.), and 4) make sure the “attic” is ventilated.
If you live in a climate where you mostly cool, then same thing, except use unfaced.