steam
For any game that we both own on Steam, I don't see the option anywhere within the Steam client to invite someone on my Steam friends list to play a game with me. This is the only menu I see when I right-click my friend in my friend's list.
How can I invite a friend to my game using the Steam Client?
As of the latest update to Steam, you can now PERMANENTLY remove games from your Steam account!
You can browse over your entire library and choose which software you'd like to permanently get rid of. But note, once you have removed a game from your library, it's gone permanently, so if later down the road you'd like it back you'll have to purchase it again.
You'll also need to watch out for some other issues. The thread linked above has noted that if the game is part of a bundle (HumbleBundle, etc.), removing one game from a "package" may require you to remove all the games from that specific bundle.
Try to block the person you are trying to add then unblock them and then add them again.
Also, have you been able to add other people?
Their friendslist may also be full!
Best Answer
The game should support multiplayer and it will only usually let you invite a friend to play when you are in a suitable section of the game, such as a multiplayer lobby or a game that has an in-game option enabled that lets friends join you. If, for example, you are in the main menu of a game, it usually will not let you invite a friend (unless that main menu shows you in-game that you can invite friends).