Q: FACETIME

Hey there, Jim421!

Sounds like there's an issue with phone calls started on your new iMac being directed to your iPhone instead of staying on your iMac. We can look at a few things. 

Take a look here: Get help using Continuity with your iOS device or your Mac - Apple Support

Check your settings

Check these settings on your iOS device:

• Make sure that Wi-Fi is on in Settings > Wi-Fi.
• Make sure that your iOS devices are on the same network: On each device, go to Settings > Wi-Fi and compare the network names.
• Make sure that Bluetooth is on in Settings > Bluetooth. 
• Go to Settings > General > Handoff & Suggested Apps. Make sure that Handoff is on.

Check these settings on your Mac:

• Go to the Wi-Fi icon at the top of your screen and make sure that Wi-Fi is on.
• Make sure that your Mac and iOS devices are connected to the same Wi-Fi network. Go to Settings > Wi-Fi on each iOS device and compare the network name with the one on your Mac.
• Go to the Bluetooth icon at the top of your screen and make sure that Bluetooth is on.
• Choose Apple menu > System Preferences. Click General, then select "Allow Handoff between this Mac and your iCloud devices." If you don't see this setting, your Mac might not support Handoff. 
• Open the FaceTime app. Go to FaceTime > Preferences and turn on Calls From iPhone.
• Go to Apple menu > System Preferences and click iCloud. Click Sign Out, then sign in again. 

You can also check here, too: Use Continuity to connect your iPhone, iPad, iPod touch, and Mac - Apple Support

Hopefully those help.  If not, reply back with which iPhone model you have and the iOS version on it. 

Cheers!