How to Place Mac Calls on Your iPhone with the Handoff Feature
The Handoff feature in iOS 8 means that you can use your Mac to place a phone call using your iPhone. For this to work, your Mac must be running OS X Yosemite, your iPhone must be running iOS 8, both machines must be signed in to the same iCloud account, and your iPhone must be within about 30 feet of your Mac.
You have several ways to send a phone number from your Mac to your iPhone:
In Safari, highlight a web page phone number, click the drop-down arrow that appears to the right of the number, and then click Call “Number” Using iPhone (where Number is the highlighted phone number).
In Contacts, hover the mouse over a contact’s phone number and then click the phone icon that appears to the right of the number.
In FaceTime, click the phone icon that appears to the right of the contact and then click the phone number that appears under Call Using iPhone.
Currently, only Macs that support Bluetooth 4.0 can use Handoff. To check, click the Apple icon, click About This Mac, click System Report, click Bluetooth, then read the LMP Version. If it says 0x6, then your Mac supports Bluetooth 4.0.
Also, you need to turn on Handoff support for your Mac. Open System Preferences, click General, and then click to activate the Allow Handoff between this Mac and your iCloud devices check box.