A digital signature is an electronic form of a signature that can be used to authenticate the identity of the sender of a message. It ensures that the original content is unchanged while in transit. Digital signatures cannot be copied by someone else. It ensures that the original signed message has arrived and the sender cannot disclaim it later.
Digital Signature Certificates (DSC) is the electronic format of physical certificate like a driving License, passport etc. All Certificates serve a certain purpose. For example, a passport identifies someone as a citizen of that country in same manner a Digital Signature Certificate can be presented electronically to prove the identity of an individual.
A Digital Signature is a tool to sign an electronic document whereas a Digital Signature Certificate is a computer based record which: