How to switch between primary and secondary cards by SMS on Apple's mobile phone?

Apple sends text messages to switch between primary and secondary cards, taking iPhone XR as an example. The specific steps are as follows:

1, open your mobile home page, and click Info to enter, as shown in the figure below.

2. Enter the information interface and click New, as shown in the figure below.

3. Enter the new interface and click the recipient, as shown in the figure below.

4. Enter the recipient number or add an address book, as shown in the figure below.

5. After adding the recipient, the default mobile phone card name will appear. Click on the mobile phone card, as shown in the figure below.

6. The option of two cards appears, and switch to the card you want to use, as shown in the figure below.

7. If the handover is successful, enter a short message and click Send, as shown in the figure below.

Related introduction:

The so-called dual card dual standby means that the same mobile phone has two phone card slots, which can support calls, text messages and other services of two phone cards at the same time. Moreover, it is necessary to distinguish between dual-card dual-standby mobile phones, because although some mobile phones can hold two calling cards, they belong to the dual-card single-mode phone mode, which means that only one calling card can be used, and the other one is always in the standby off state.