1. Save the QR code image to Photos.
   • Log in to your account.
   • Go to Manage your eSIMs.
   • Select the eSIM and open the QR code.
   • Save the image (or take a screenshot and crop it).
2. On your iPhone, go to Settings.
3. Tap Mobile Service or Cellular Service.
4. Tap Add eSIM.
5. Tap Use QR Code.
6. Tap Open Photos.
7. Select your saved QR code.
8. Tap Continue.
   • Do not close the window during installation.
9. Allow up to 10 minutes for activation.
10. Tap Done.
11. Set Default Line to Primary.
12. Set Mobile Data to your eSIM.
13. Go back to Settings → Mobile/Cellular Service → (your eSIM) and turn Data Roaming On.

Source: https://support.limitflex.com/en/articles/9642219-how-to-install-an-esim-on-an-apple-ios-17-device-using-a-qr-code-from-your-photos