Identity verification depends on the country. In certain cases there may be limitations. There are many eSIM sellers, like Airalo, Jetpac, Saily, Holafly and more. You can buy the eSIM with an eSIM package (for data, mostly, but some also sell voice/SMS) for a country or region, activate it (or wait for it to activate when the phone connects to a local network at the destination) and use it.
It’s so simple and convenient. Once you’ve returned back, you don’t necessarily have to delete the eSIM from the device. The iPhone models that have had eSIM support allow you to have a total of eight eSIMs on the device. You can activate (i.e., turn on) only two lines at any point in time.
So even if you have two numbers where you live, you can turn one off, use that slot and turn on your travel eSIM and then later switch back.
All the eSIM sellers provide clear and detailed instructions on how to install and activate the eSIM.