Preferred line
What's the difference between last used, primary, or cellular data
iPhone 13, iOS 16
User profile for user:
faith185
User level:
Community Specialist
Hi Bdstevenson,
Welcome to Apple Support Communities. It sounds like you are setting call or message accounts for your contacts. Right?
As mentioned in Edit contacts on iPhone - Apple Support, "On models with Dual SIM, when you call or text a contact, iPhone uses the same line you used for your previous communication with this contact by default. To choose a preferred line for phone calls and SMS/MMS message conversations, select the contact, tap default (below the contact’s name), then choose a line."
However, you can set a default number for calls and messages using the following guidance from Using Dual SIM with an eSIM - Apple Support.
1. Tap the contact.
2. Tap Preferred Cellular Plan.
3. Tap the number you want to use with that contact.
Take care.