Drip the wax onto your desired location, and then press a stamp into it. You can use the stamps designed for this process, usually made from brass, or even a rubber stamp. Most stamps are vulcanized, meaning they are able to withstand the heat of melted wax. By adding pigment powders or glitter, you can create a raised image that is beautiful and unique.
One drawback to the "seal" technique is that it creates a rather heavy piece of wax on your paper, which may add to your postage costs. Take note of this when creating your budget.
Most craft stores have many examples of wax techniques available, and some offer classes on the process of applying a wax seal stamp.