How to send messages with iphone 12 extension?

Apple iPhone 12 supports dual card dual standby. How to choose the primary card or the secondary card to send short messages, and where is the mobile phone number for sending short messages? Let's take a look at the selection method of primary and secondary cards for iPhone 12 SMS.

1. Open iPhone and click Info.

2. Click on the top right corner to write a new message, enter the mobile phone number of the recipient, or click the+sign at the back to select the recipient from the address book.

3. When editing the short message text, the main number prompt will pop up. If you want to switch to a secondary number, please click this button to switch.

4. If the message sent by this contact was sent to your main number before, but you are now in the secondary number state, you will be prompted that "this number has been changed to the main number". At this point, if you reply directly, it will become a main card message.

5. If you want to send a message with a different card, you need to delete the previous message. If you don't want to delete the previous SMS, you need to use the card-fetching pin and take out the main card before sending SMS with the secondary card.

6. To set the primary and secondary phone numbers of iPhone, you need to enter Settings-Cellular Mobile Network, and then you can see two phone numbers to determine the primary and secondary phone numbers.