Most puppies do not require a bath until they are at least four weeks old, if not older. However, if your two-week-old puppy has already created mischief and gotten himself extremely dirty in some areas, you can spot clean him. When you do this you will need to make sure he stays constantly warm. Do not submerge him in any water. Spot cleaning your 2-week-old puppy can be done with a warm wet washcloth or with even a dry towel or soft cloth. If your puppy's mother is around and available, she will always provide the best bath your 2-week-old puppy can get.
Your two-week-old puppy is still discovering his world. He is very fragile, and his skin is extremely sensitive. If you don't need to bathe him at this point, don't. If you do, understand that he needs to stay warm in order to survive. So make this spot bath very quick and get back to warmth as soon as possible.