Products are items you sell. These can be items you make or items other make but you sell them. For example, you might know how to crochet so you make hats and sell them to your friends. Or maybe you paint pictures and your friend pays you to make a custom picture. You might also sell items someone else made. For example, you might have lots of toys that you want to sell to someone. Those toys are products.
Services are things you do for someone else that you charge them for. For example, kids frequently do yard work for other people. You might also babysit or tutor younger kids.