How does iphone switch cards to send SMS?

Tool: iphoneXR.

System version: ios 14.

1. Take Apple XR as an example, click Information to enter, as shown in the following figure:

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 dual card option appears, and switch to the card you want to use, as shown in the following figure:

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