Each class uses their own class specific equipment and weapons. Accessories such as rings, bracelets, necklaces, and earrings are shared amongst all classes.
You are able to reinforce or enchant equipment to give it better stats or bonus stats. You may also level down equipment that is a few levels too high for you to use, up to a maxmum of 15 levels lower (except Unique and Honor gear, wich is level locked).
Transfering is the "skinning" of another piece of equipment over your current equipment. This is completely visual and doesn't not improve or lower the stats of your equipment.
For more information about these topics, please visit the pages and categories listed below.