Before your Round
From the 'Me/Profile' tab, tap the 'Settings' icon on the top-right to open the Profile Settings. On the 'Profile Settings', scroll to find the Game information and set your 'Distance Units' as meters (Metric) or yards (Imperial). Tap 'Save' on the top-right to record your preferences.
During the Round
On the hole map, tap the 'Settings' icon on the right to edit your Distance Units.