Digital signature is permission and proof done through a computer that an authorized person has agreed to something.
When a signer authorizes something, they use their private key known only to them, to encrypt information along with a stamp of the time of signing. If the information is somehow modified, the time stamp will be altered and the digital signature becomes void and invalid.
The person receiving or verifying the signed and encrypted information uses the signer’s public key to verify the information came from the signer.
Digital signatures are used by cryptocurrency systems to allow the owner to send and receive money.