Note: This will require that both your iPhone and the device you plan to receive the calls on be signed in to the same Apple ID. It is likely that you already have this set up, but if not you can sign in to your Apple ID by going to “Settings”, “Accounts and Passwords”, and then “iCloud”.
On your iPhone, go to “Settings”, “Phone”, and then “Calls on Other Devices”. From here, enable “Allow calls on other devices”, and then select the names of all the devices that you want to receive calls on. After that you should be all set, and any calls to your iPhone should also appear on your selected devices.