You can access personal settings by going to Settings on the menu, then Personal settings in the Settings screen.
Here you can choose:
Units of measure: Metric (meters, kilometers, kg) or English (yards, miles pounds)
Your height and weight: These are not required, but if specified will make calorie estimates for activities more accurate. If you sync with the Apple Health app and allow Racefully to access these measures, they will update automatically.
Your gender: This is not required, but if specified will be used in calorie estimations, and also the use of pronouns in the app e.g. "Maria shared her run with you"