The intellectual property associated with the design in the product might require additional authorization from the original rights holders (namely owner of the brand).
If you have the rights to IP in the product cleared via other means, for instance, you may be the advertising agency for a brand/IP owner or you may be the brand/IP owner itself purchasing user generated content. Given you have the rights clearance through other means, you may use the product in the ways defined by Royalty Free License. If you do not have the IP rights cleared and cannot prove the ownership of IP rights, the terms of Editorial License applies.
Royalty Free License allows you to use the product without the need to pay royalties or other license fees for multiple uses, per volume sold, or some time period of use or sales. Products published with this licence may not be sold, given, or assigned to another person or entity in the form it is downloaded from the site, but can be used in your commercial projects multiple times after paying for it just once.
Editorial license gives a permission to use the product only in an editorial manner, relating to events that are newsworthy, or of public interest, and may not be used for any commercial, promotional, advertising or merchandising use.