Why can't I activate calls on other devices?

[iMore Question]

Why can't I activate calls on other devices

I can't activate calls on other devices on my iPhone 6s

 

[Rob Phillips]

Why can't I activate calls on other devices

Welcome to iMore! If you're asking how to answer incoming calls on other devices, go to Settings > Phone > Calls on Other Devices, and make sure you have the feature enabled. You'll want to make sure you're signed in using the same Apple ID on your other devices and that you have the feature enabled on them as well.
If you're still having problems restart all of your devices. After that, visit the Apple Support link below. Continuity has a few limitations and nuances that you should be aware of.
https://support.apple.com/en-us/HT204681