While a traditional text (SMS) must be connected to a phone number, Apple features like iMessage and FaceTime only need a Wi-Fi or data connection to work -- making them a perfect solution for iPhone or iPad users with an eSIM data plan.
Here are three steps to making sure iMessage is set up to work correctly with your new eSIM:
1. Go to "Settings" and choose "Messages"
2. Make sure iMessage is toggled on, and tap "Send & Receive"
3. Your Apple ID (email address) should be checked off to receive and respond to iMessages
If you have followed these steps and iMessage is still not working correctly, please read this post for tips on resetting iMessage.