Handoff / transfer phone calls between iPhone and Mac

Hi MadParty,

Welcome to Apple Support Communities.

To get that FaceTime call handed off from your iPhone to your Mac, make sure you have enabled "Allow phone calls on your other devices" from iPhone:

"You first set up your iPhone, and then set up your other devices.

1. On your iPhone, go to Settings  > Cellular.
2. If your iPhone has Dual SIM, choose a line (below Cellular Plans).
3. Do any of the following:

• Tap Calls on Other Devices, turn on Allow Calls on Other Devices, then choose the devices on which you’d like to make and receive calls.
  • This allows other devices where you’re signed in with the same Apple ID to make and receive calls when they’re nearby your iPhone and connected to Wi-Fi.
• Tap Wi-Fi Calling, then turn on Add Wi-Fi Calling For Other Devices.
  • This allows other devices where you’re signed in with the same Apple ID to make and receive calls even when your iPhone isn’t nearby.

On your other devices, do the following:

On your iPad or iPod touch: Go to Settings > FaceTime, then turn on FaceTime and Calls from iPhone. If you’re asked, turn on Wi-Fi Calling.

On your Mac: Open FaceTime, choose FaceTime > Preferences > Settings, then select Calls from iPhone. If an Upgrade to Wi-Fi Calling button appears, click it, then follow the instructions."

Allow phone calls on your iPad, iPod touch, and Mac - Apple Support

We hope this helps.

Cheers!

When you’re on your iPhone, try tapping the speakerphone button while on the call, and you should see a dropdown list, and then you can select your iMac.