Is it possible for me to give my friend the game I bought on mu xbox one(digital copy) so it will be his know and if i wanted to play I would have to buy again?
But, a popular way to share with one other person is to use Home sharing.
Basically, the xbox rule is that your profile needs to own a game to be able to play it. A nice feature though is that on your "Home" xbox (designated by going to settings) any profile logged into that xbox can play your games. For example, if a friend comes over and logs in with their profile, they can join you even if theyve never bought the game. If you were to go to their house on their Home xbox and download that same game, you would be able to play, but they wouldnt (you're not sharing it anymore, because its not your profile's Home xbox).
So what you can do to circumvent this situation is to log into your friend's xbox (with their permission of course) and set their xbox as your Home xbox (and vice versa, if they want to share games with you, but that's not necessary). It can still be their Home xbox too, its a per-profile setting.
After that, since theyre always playing on "your" Home xbox, your profile shares all your games with them, even when you're offline (it even works with some DLC). When you log into the xbox at your house, even though it's not technically your Home xbox anymore, your games are still available.
This works one-way or two-way; your friends xbox can be your Home xbox and their Home xbox, and youll just share your games with them. If they set your xbox as their Home xbox, then you are both sharing your complete libraries with each other.
Note: this does not work (at time of posting) for the recently released Backwards Compatible games, even if you both are in the Xbox Dashboard preview program.
Also, one nice feature is that you can set a preference for your profile to "automatically download purchases to my Home xbox". So if you share with your buddy and you decide to buy a game, as soon as it starts downloading on your xbox, the download has started on their xbox too. This can also be disabled at any time.
It should also be noted that this is in no way subversive; this is an xbox feature. It's just not publicized or explained very well.