A signature is a special way that people write their name to let others know that they understand or approve of something that was written. A signature is often used to sign a contract, a cheque, or a petition.
There are many ways to write a signature, and signatures may look different depending on your location. In the United States, many people have a signature which is made from writing their name in their own handwriting, often in cursive. Some signatures may be written in a different style than normal writing, which may make it difficult to read. Some people practice autographs, or fancy signatures that are hard to copy.
Hundreds of years ago some people used sealing wax to make a copy of their signet rings next to or instead of a signature. This was called their "seal. This is where the term "seal of approval" comes from. Some formal documents still use an official wax seal, such as a coat of arms.