You can wear a wide range of items on your body by simply dragging and dropping it on the bodyparts you want to wear it on. The term equipping may also refer to wearing an item, sometimes it's falsely used to refer to activate an item with a double-click. Some items require to be worn on the correct bodyparts, but everything can be equipped to your hands.
Some items like armour or shields need to be equipped to be of any use, others can be worn for decoration or roleplay. Clothing and armour equipped to the regarding bodyparts are not yet shown, but everything in your hands will have its model shown on your avatar.