Basically it means that if you purchase an item from Tess at her shop by the postmaster in the tower, or obtain the item through other means, you will then have the license for that particular item, and can then claim it from the respective kiosk for that item, allowing you to delete it if you want, and claim it again later, or claim it on multiple characters. Some items can only be purchased through Tess, but others, like emote packages can drop as nightfall rewards.