How to install an eSIM on iPhone
On iPhone the install path is Settings → Cellular → Add eSIM and then scanning the QR code from the activation email. There is no SIM tray to open and no card to wait for, and the Mongolian SIM stays in the phone. Keep Wi-Fi on while you scan, because iOS downloads the profile over the internet.
Where is the eSIM menu on iPhone?
Settings → Cellular (Mobile Data on some models) → Add eSIM. On recent iOS versions the same entry may be labelled Set Up eSIM.
Can my Mongolian SIM and the eSIM work together?
Yes, on dual-SIM capable iPhones both lines stay active: keep your Mongolian number for calls and SMS and give Mobile Data to the GlobalSIM eSIM.
How do I know my iPhone supports eSIM?
Open Settings → General → About and look for EID, or dial *#06#. If an EID is shown, the phone can install an eSIM.