Clothing creases, make the creases start and end at different contact points. The fabric if it is looser fitting will drape over the parts they place over, for example, the arms will create creases near the bottom travelling up as the most fabric is there.

Things like, fabric type, angle, and where the clothing is overlaying will factor into how the creases appear. Use references, apply some lines to create the creases and put some darker lines in there to show depth a little more.

You don’t have to do this, but creases in clothing goes a long way in character designs that have a more normal appearance.