Apple Watch set up for family member
If I set up an Apple Watch se with cellular for my wife using my iPhone 13 will I need to add another phone line
Apple Watch
From my understanding of how the family line works, the member with the Watch that does not have an iPhone will get a new number that you can call. Below are excerpts from the support document I provided.
From the section How It Works.
With Family Setup, your family member who doesn't have their own iPhone can use their Apple Watch to do things like make phone calls, send messages, and share their location with you.
From the section What You Need, specifically the first bullet point
- An Apple Watch Series 4 or later with cellular,* or Apple Watch SE with cellular, with watchOS 7 or later.
and the asterisk footnote. * A cellular plan isn't required to set up an Apple Watch for a family member, but is necessary for some features.
From the numbered section, #7 Setup cellular and wi-fi
If your iPhone cellular provider supports Family Setup, you can add the watch to your plan. If your carrier doesn’t support it, you might be able to use an alternative carrier. Then you can set up cellular on the watch later.
Next, choose whether to share your current Wi-Fi network with the Apple Watch.
While it isn't necessary to setup the cellular, if you want the Family Member to have the ability to use the phone to make and receive calls, you would need to do that. The carrier determines, but it would require a new line if you wish to setup cellular.