Paperwhites can be potted upon receipt. They can also be stored in a cool, dry location for many weeks. Many people pot their bulbs in batches, one after the next, to keep the fragrance coming.
It’s not unusual for paperwhites to begin to sprout while in storage. The shoots emerge an inch or two and then stop, as though the bulbs realize they are getting ahead of themselves. The shoots often curl around the bulbs, pointing opposite gravity. After the bulbs are potted, the shoots straighten up.