How to switch between primary and secondary cards when texting iphone?

Take iPhone 1 1 as an example. How to switch between primary and secondary cards when sending SMS on Apple mobile phone is as follows:

1, open the information program of iPhone 1 1 , click the letter icon to create a new message.

2. Enter the mobile phone number of the recipient, or click the "+"sign behind the recipient to select the recipient from the address book.

3. If the recipient number is not in the address book, clicking Edit SMS will pop up the current default SIM card; If the recipient number is in the address book, the current default SIM card will pop up directly after selecting the recipient.

4. Click the current default SIM card, and the minor number and major number will pop up at the bottom of the screen for selection.

5. If you select the secondary number at this time, you will switch to the secondary number to send short messages.

6. It should be noted that if a contact with a short message record stops at the short message interface as shown in the figure below, then the current short message record must be deleted before the main and secondary cards can be switched. If you don't want to delete messages, take the SIM card that doesn't send messages out of your mobile phone and put it back after sending messages.