Tap the Multiplayer button Visible in the above screenshot. If you are missing the Multiplayer button and see the background as “Phase 10 Master’s edition” please delete and re-install the app.
You should now see the above screen but may not have any games in progress, tap “Create game" to start the creation process.
On this screen you will want to select the Invite Friends option.
Now tap the blue “+” symbol in the top right corner.
You can select one of your friends from this list
Which will put a check mark. Now tap “Add”
You are brought into the match. Play your turn
Your opponent will become highlighted. If you know they are in the app and ready to play you can wait for them to take the turn or back out to the lobby
The lobby view will show all the games in progress. The initials of you friend will show up in their position.