There are several ways to post:
1.Check in your goals:
Go to Me page > scroll down and find Check-ins > Add a Goal > tap the Goal to check in.
Or go to Feed page > tap the upper right button > Add a Goal > tap the Goal to check in.
After checking in your goal, you will be able to send posts. Please be noted that for steps or time related goals (10k, 6k, and 3k steps, 30 minutes, 60 minutes daily workout), you need to reach the number limit to be able to check in. For other goals (drink more water or any other customized goal), you can check in at any time.
2.Post your challenge progress:
Go to Explore > Events > join a global challenge > tap and enter the challenge page > tap posts > select "post"