How to set the traffic of which card for Apple dual-card mobile phone?

Apple's dual-card switching traffic needs to enter the system settings, and the primary/secondary card traffic is set in the cellular network.

Tools/materials: iPhone 13, iOS 15.0.2, setting 1.0.

1, open the cellular network.

Go to Apple System Settings, find and open cellular network settings.

2. Open cellular data

Locate and open the cellular data settings in Settings.

3. Exchange traffic

In cellular data, you can choose the primary card or secondary card that currently uses traffic, or you can switch traffic independently by turning on the function that allows switching cellular data below.