What do you call sticky paper placed on a letter?

There are a few terms you could use to describe sticky paper placed on a letter, depending on the context:

* Seal: This is the most common and general term.

* Sticker: This is a broader term, but it can refer to any type of adhesive paper.

* Label: This implies that the sticky paper has some text or information on it.

* Security seal: This term is used for sticky paper specifically designed to deter tampering with a letter.

* Tamper-evident seal: This is a more formal term for a security seal.

* Tape: If the sticky paper is a strip, you can call it tape.

The best term to use will depend on the specific situation and the type of sticky paper being used.