A digital signature is like an electronic driver’s license or passport that proves your identity. A digital signature usually contains your name and email address, the name of the organization that issued it, a serial number, and an expiration date. Digital signatures are used for certificate security and digital signatures.
Digital signatures contain two keys: the public key locks, or encrypts data; the private key unlocks, or decrypts that data. When you sign PDFs, you use the private key to apply your digital signature. The public key is in a certificate that you distribute to others. For example, you can send the certificate to those who want to validate your signature or identity. Store your digital signature in a safe place, because it contains your private key that others can use to decrypt your information.
For full details on how to create a digital signature, please visit: https://helpx.adobe.com/acrobat/using/digital-ids.html.