The new iPhone X series – the XS, XS Max and XR – is the first iPhone to feature dual SIM technology. This was not immediately possible, but was delivered with yesterday's update 12.1. This means what that means.
To support two SIM cards, the new X Series iPhone phones use a traditional SIM slot for their primary number and an eSIM for the secondary account. Although we have a deeper explanation for what this means, it is succinct that you can not just put a pair of SIM cards in your phone and let them work.
Instead, your second carrier must support the eSIM technology (which most major do now) and you need to set it up yourself. The good news is that it's just stupid to set up your second carrier. That's how it's done.
Note: Primary network operators use the traditional SIM slot. Only the secondary carrier can use the eSIM slot. If you only have one carrier, you have nothing else to do. It's also worth noting that this is not yet available on Verizon ̵
First, jump to the Settings menu. Select the option Cellular.
Tap Add Cellular Plan, which instantly opens a QR scanner. If your mobile service provider offered a QR code, scan it here. All relevant information is added immediately, and you can proceed immediately.
If you do not have a QR code, you must enter this info manager. At the bottom, tap the Enter Details button manually.
All information needed here should be provided by your carrier – if you miss something (other than the verification code, which is optional) You may need to call your mobile service provider again to get the details ,
The SM-DP + address is essentially just account information that connects your phone to the wireless service provider, and the activation code is similar to a password that can be used to complete the connection.
After the correct details have been entered, the connection should be established. Done and done.