First of all, there is no definitive answer to this question — as this largely depends on your specific situation and needs. Digital signatures are typically used when you want to guarantee a level of security and ease of use for your transactions — for example, for legal, healthcare, or HR documents.
Digital signatures are used to meet three important goals of information security: integrity, authentication, and non-repudiation. As such, digital signatures help enforce security during data transfers.
Yes, there is. A digital signature is a more secure electronic signature that is generated using a digital certificate and cryptographically bound to the document using public key infrastructure (PKI). The digital certificate is unique to the signer and obtained from a trusted 3rd party such as a trust service provider (TSP) or certificate authority (CA) after verification of the signer's identity.