The Network Play tab on the Settings panel controls the Online Play feature. The checkmarks in the screenshot shown indicate that the features are turned on.  Unchecking Online Play disables Game Center for this app and removes the Online Play button from the play area of the screen. To completely disable game center for all apps, see Disable Online Play (Game Center).  If you only wish to turn off Voice Chat, but still allow online play, you can uncheck only that item.

The Friends Only option ensures that connections are only made to those people in your Game Center friend list.  Auto-matching is a Game Center feature that allows an online game to be established with anyone, including strangers.  Auto-matching is not recommended for this game, and the Friends Only option prevents these random connections from being established.

For safe and fun Online Play, children should be assisted to ensure that they only connect with the family and friends that you approve while using Game Center.

Next:  Online Play Launching