Just send them the link https://airawarelabs.com/airtrack and ask them to sign up! And if they follow you on Strava and see the data on your feed, they can sign up directly. We’ve also added some sharing features in the AirTrack app - check them out! You can also ask your friends to scan this QR code with their phone camera!
If you are a Premium user, you can create Leaderboards to involve your friends. If you are a Free user, you can join Leaderboards.