Along with the letter, a real and unbroken wax Hogwarts seal on an unopened envelope is also included. WOMAN HAS THE WORLD'S LARGEST ‘HARRY POTTER’ MEMORABILIA COLLECTION Chiswick Auctions ...

This is a method of folding the paper of your letter in such a way that it becomes its own envelope, often using slits and tabs running throughout the creased letter. A wax seal was often employed ...