During old century, wax seal is used by law, bank and corporate industries. It is to verify something such as a document that is unopened, confidential and to verify the sender’s identity. Wax was used to seal on the letters from the 16th century envelopes.
For new century, the wax seal was not only used on documents. More and more people like to use wax seal on wedding cards, birthday cards, or as gift etc.