All wearable devices do not connect directly with the Achievement app, the data is fetched from your fitness app and synced to your Achievement account. While we do not currently have the Activity app available to connect with Achievement, you can connect you Apple Watch to Apple Health for us to log your activities to Achievement.
To do so, please open your Apple Health app, go to sources, and ensure that your Apple Watch is one of the devices connected to your Health app. Here is a link to Apple's Support article with more information about manually syncing data and connecting.
What can I do to ensure my Apple Watch activity syncs with Achievement?
To ensure your activities sync with Achievement as accurately and fast as possible, we ask that you sync your Apple Watch to Apple Health once a day and open the Achievement app. Doing this will help ensure that you earn points for all your activities. We will be unable to award points for activities that are over 2 weeks old and have not yet been synced with Achievement.
Also check that both your mobile device and Apple Health app have the latest updates. If you continue to face problems syncing your Apple Health activity data, please send us more information here with screenshots of your missing Apple Health activities (if possible) and we can look further into the issue.