Source :  Internet

The eSIM  is a SIM card integrated right into the device's circuit board. A programmable SIM card enables you to change carriers without physically exchanging SIM cards. The carrier's ability to remotely reprogram an eSIM makes it easier for the user and more adaptable for the carrier.  

eSIM, is a separate chip implanted within the device.

eSIM is more adaptable because the carrier may remotely reprogram it.

Advantages of eSIM:

Improved adaptability: With eSIM, consumers may change providers or plans without physically replacing their SIM cards. Those who often travel or wish to transfer providers will find it more convenient.

Smaller form factor: Because eSIM is smaller than a conventional SIM card, more room may be used in the device's design.

Remote activation and provisioning: The carrier may remotely activate and provide an eSIM, eliminating the need for physical SIM cards and improving consumer convenience.