It is normal for acoustic players to sit down when they play guitar. For many popular styles of guitar like folk, blues and rock, a good way to hold a guitar while sitting down is to rest the waist of the guitar on your right leg, rest your right arm over the bout of the body, and hold the neck from the bottom with your left hand.
whereas players of different types of guitar usually hold the guitar with the waist of the body resting on their left leg bringing the neck higher in the air and closer to the face to be able to see one’s own playing since those are inherently more technical and intimate styles of playing.