The difference is whether it is an individual or a unit.

Personal signature (seal) means writing your own name, and if there is a seal engraved with your own name, it is also a seal. Generally, banks often carve seals, and banks have the method of scanning and engraving to confirm customers.

The signature (seal) of the company means that the general signature is the handler of the incident, and the seal is the official seal of the company.