A loveseat is essentially a short two-seat sofa, so it is one of the easier upholstered pieces to move. Two people and a doorway measurement are usually all you need.
Pro tip: A loveseat is short enough that one person can often balance one end on a shoulder while the other steers, useful on stairs.
Watch out: Do not carry a loveseat by its arms alone; support it from the solid base to avoid loosening the joints.