Ensure you have a strong internet connection to finish the process, and don't remove the eSIM from your device because it can't be reused afterward. 

Step 1
Go to 'Settings' > 'Cellular'.
How To Install eSIM on iPhone
Step 2
Tap 'Add eSIM'.
Click Add eSIM
Step 3
Tap 'Use QR code'.
Set Up eSIM with QR Code
Step 4
Scan the QR code. The best method is to take a screenshot and display it on another device for scanning.
Scan QR Code
Step 5
Tap 'Continue'. This step may take a few moments.
Activate eSIM
Step 6
Tap 'Done'.
Click on Done to complete setup
Step 7
Click the eSIM that was added under 'Cellular Plan Labels' to change the name of your eSIM.
Rename eSIM in Mobile Plan Settings
Step 8 
Update your eSIM name to 'StaffTraveler' and
select 'Done' on the upper right side.
Change eSIM Name to Voye and Confirm
Step 9
Tap 'Continue'
Confirm
Step 10
Continue with the installation process
and mark 'Primary' for 'Default Line'.
Complete setup and select 'Main' as default line
Step 11
Continue with the installation process
and mark 'Primary' for iMessage & FaceTime.
Set iMessage and FaceTime as Primary during Installation
Step 12
Congratulations!
Your eSIM was added to your 'Cellular' page.
Welcome! Your eSIM is now active on your "Cellular" page.

To verify that your eSIM works on iOS:

  1. Tap 'Settings' > 'Cellular'

  2. Turn your StaffTraveler eSIM on

  3. Turn on 'Data Roaming' on your StaffTraveler eSIM

  4. Turn your Wi-Fi off

  5. Tap 'Mobile Data'
  6. Select StaffTraveler eSIM
  7. De-select 'Allow Mobile Data Switching'

  8. Try to use the internet. Note that the initial synchronization might take a few minutes

You are now connected! To return to your primary SIM, set your Mobile Data to your primary SIM and turn off the StaffTraveler eSIM.