I have N edges forming a loop, and the edges are not coplanar. I want to fill this N-gon with a face, but that does not make sense (at least such a face will not be 3d-printable) since the points are not coplanar. So selecting all N edges and then pressing F, though it seems to show a face in Blender, is not the solution for me. So I'm content with simply choosing a new point that is roughly at the center of this loop, and then forming N triangular faces with the N edges. This will succeed in closing the loop with a "face". Can someone explain how this is done?
Of course, if someone can explain how I can nudge the N points to become exactly coplanar (they are almost coplanar right now, but not exactly), then of course filling the N-gon with a single face would be acceptable and a more clean solution.