When you have two
cards inserted on your phone, only one card can be used to connect to the Internet at a time.
If you're using
Google or third-party apps, you can also choose which one to use as the default card for making phone calls and sending SMS/MMS messages.
Note: Dual SIM card support varies by phone model, region, and country.
Home screen, swipe up and then tap
Data network, and then choose the card to use for connecting to the Internet. .
Voice calls and
SMS messages respectively to set the default card to use for making phone calls and sending SMS/MMS messages.