I'm not receiving gifts, keys or power ups, from some friends that I know are sending them ...

I believe that you add friends via Xbox Live (so, you'd look for them via xbox.com and use their profile to add them). Then you can send keys, etc., once per day to each of them. There is a menu option to send gifts to your friends in the same menu that
you receive the gifts.

On the main screen below the play button, there are a series of icons. The one to the far left of the group takes you to the gifts section. You can send and receive gifts (keys and bonus items) to / from friends, and you should be able to collect the community
goal rewards here as well.

She tries to send me friend requests from the Xbox app on her phone and I don't receive them. And when I send some to her, they don't come in. She tried logging into my Xbox account and accepting it that way, on her screen, it says that I'm her friend
but she doesn't show up on the friends list on my screen.

Yeah, I know. I'm not buying the game, I received the product key from a friend and redeemed it on the Xbox app. I thought it would appear and download to play it. apparently not

Hello Mirenheart,

Thank you for posting on the Xbox forums. We understand that you are unable to select a friend from your friend's list so that you can send your friend a gift. Are you attempting to send the gift on an Xbox One, a Windows 10 computer or a mobile device?
If you are using an Xbox One, we suggest
power cycling the console by holding down the power button on the console for ten seconds. If this does not resolve the issue, we recommend trying to

send the gift through the Microsoft Store website on a different device like a cell phone or tablet. Be sure to let us know the results
Mirenheart!