When your Mac, iOS devices, and Apple Watch are near each other, you can use Handoff to pass a presentation you’re working on from one device to the other. For example, if you’re working on a Keynote presentation on your iPhone and you’re near your Mac, you can pick up the presentation on your Mac and finish the presentation there.
Handoff requires:
OS X 10.10 or later on a Mac
iOS 8 or later on an iOS device
Bluetooth 4 (Bluetooth LE) on both systems
Both devices signed in to iCloud using the same Apple ID on the same Wi-Fi network
You set up Handoff in System Preferences on the Mac (in General preferences, select “Allow Handoff between this Mac and your iCloud devices”) and in Settings on your iOS device (go to General > Handoff, then turn on Handoff).
Open a presentation on your Mac.
When your Mac is near the iOS device you want to hand off to, a Handoff icon for Keynote 
appears in the bottom-left corner of the device’s Lock screen.
Note: Only the app you’re currently using can hand off your work.
On the iOS device, swipe up on to open the presentation.
You can also see the Handoff icon when you double-click the Home button to reveal the multitasking screen. Tap Keynote at the bottom of the screen to pick up where you left off.
On an iOS device or another Mac, open a presentation.
When the device or other Mac is near the Mac you want to hand off to, the Handoff icon appears on the left side of the Dock.
Click the Handoff icon to open the presentation.
Tip: If you’re playing a presentation on a Mac, you can also use Handoff to turn the iOS device into a remote control for the presentation. See Control a presentation with a remote.
For additional instructions on setting up and using Handoff, click the desktop to switch to the Finder, choose Help > Mac Help (from the Help menu at the top of your screen), then search for “Handoff.”