A digital certificate, also known as a public key certificate, is used to cryptographically link ownership of a public key with the entity that owns it
Digital certificates are for sharing public keys and public keys are for encrypting data and authentication
Its used by web browsers and web servers for secure communication and to share keys for encrypting and decrypting web content
Certificate Authority is any entity that issues digital certificates to verify the identity of users, applications, or organizations. That is third party certification