If a game is decided by a shootout, the winning team is credited with a single extra goal for settlement purposes. That goal is included in the final score for Total Goals bets.
For example: a game finishes 3-3, and the home team wins the shootout. For settlement, the final score is 4-3, so the total is 7 goals. If the total was set at 6.5, a bet on the over wins.
For more information, see the General Rules, Tickets & Wagers article.