Apple Handoff can be very useful but there’s just one thing. The app you’re using must be in the foreground to hand the document off. Of course there are other important things to know, like you can’t hand off apps not part of Apple’s software suite, or it stops the offer for handoff if your devices are not in close range. But here’s an example of how you might find it useful.

You’re browsing the web in Safari looking at replacement widgets find something you want. You’re about to take off with the phone to start shopping. If the phone’s in the car or a distant part of the house, Handoff won’t work. But if the phone is with you as you leave the computer, handoff icon is there. Just click on it to continue the search on the phone. Now the most important thing is the browser must be the front application, not in the background. Try it out. Make sure Handoff his enabled on both devices and open a Safari page. Now look at the phone or pad. You should see the handoff icon for Safari in the phone’s dock icon. Now either hide safari (command H) or switch to another app or the Finder. The handoff icon disappears on the phone. 

Your best practice if you don’t leave apps open on the computer when not in use, is to do the handoff, then quit the app. Knowing this can be helpful with a variety of tasks.