What is an eSIM?
An eSIM is a digital SIM profile on the phone. There is no plastic card to insert.
You install a profile from a QR code or an activation string. The phone must already support eSIM, and it must be unlocked if you want a plan from another provider. A travel eSIM is a data plan for the countries listed on that package. It does not replace your main number unless the package says it includes calls.