I want to transfer my eSIM from one iPhone to another

See these comprehensive instructions from Apple:

About eSIM on iPhone - Apple Support

If, after you've tried them, you're still having issue, post back with questions.

Hey appleusernaming

1. Ensure compatibility: Both iPhones must support eSIM technology, which is available on many newer iPhone models. Check the specifications of both devices to confirm eSIM compatibility.
2. Back up your data: Before transferring the eSIM, it's a good idea to back up your data on both iPhones. You can use iCloud Backup or iTunes/Finder Backup to create a backup of your data.
3. Deactivate eSIM on the original iPhone: Go to Settings > Cellular > Cellular Plans on your original iPhone. Select the eSIM you want to transfer and choose "Remove Cellular Plan." Follow the prompts to confirm the removal of the eSIM.
4. Activate eSIM on the new iPhone: On your new iPhone, go to Settings > Cellular > Add Cellular Plan. Follow the prompts to scan the QR code provided by your carrier or enter the activation information manually to activate the eSIM on your new device.
5. Restore your data: After activating the eSIM on the new iPhone, you can restore your data from the backup you created earlier. If you used iCloud Backup, you can do this during the initial setup process or by going to Settings > General > Reset > Erase All Content and Settings, then selecting "Restore from iCloud Backup" during the setup assistant.
6. Test the eSIM: Once the transfer is complete and your data is restored, test the eSIM on your new iPhone to ensure that it's working properly for calls, texts, and data.
7. Contact your carrier: Depending on your carrier, you may need to contact them to inform them of the eSIM transfer and to ensure that your service is activated correctly on the new device.