Every activity of any sport can be marked as race by simply checking the respective checkbox. Activities marked as race will generate a new entry as race result. You can add and edit some of the race result details such as the official distance and duration (which may differ from what you have stopped on your device) and your placements in the event.
Please make sure that you enter common distances exactly. The result will be treated as 10k race if and only if the official distance is entered as 10.00 km. This applies in particular for half-marathons (21.10 km) and marathons (42.20 km).
RUNALYZE comes with an activity type for races. Choosing this type for an activity does not mark it automatically as official race (as this activity type is not fixed and can be renamed or enitrely removed).