How do I invite a friend in to my game in 1.0?

[Sky_Strike_Inferno]

I cannot find invite button.

[Brevan]

Hard to answer the question since it isn't clear if you're both in the game already (so invite to party) or not.

Join party: While in the game, open the party information window (default hotkey is 'i'). In the row for your friend, there's a button to send them a party invite. They need to open the party window and accept the invite (for this game session you'll see their health bar and can't hurt them). There is also a button beside the party invite that lets you be allies (permanent, now you can't hurt them). Note that the "can't hurt them" feature can be turned off in the game settings (one of the tabs when you load a game.

Join game: When you're ready to load your game, make sure you've set the Server to Online (at least visible to Friends), and load the game. Once the game is loaded, you can right-click your friend's name in Steam Friends and send them an invite to join, or when your friend is on the 7DtD main menu, they select Join a Game -> Start Search -> Friends tab -> Select your name and join.