What is signing?

In web3, "signing" is a way to prove that you are the owner of a wallet. It works like a special kind of stamp that only you can make.
First, you take your message or transaction and turn it into a secret code called a "hash". Then, you use your special stamp, called a "private key", to encrypt the hash. The result is a special code that only you could have made, called a "digital signature".
When someone gets your message or transaction, they can use a special key called a "public key" to check the signature. If the signature is valid, it proves that the message or transaction really came from you and hasn't been changed by someone else.
This is like having a special secret handshake that only you and your friends know. If someone else tries to pretend to be you and use your handshake, your friends will know it's not really you.