If you want to remove a Happier account, you can easily do that with a special removal link.
I’ll show you below how I managed to close my profile using a desktop computer:
1 Click on this removal link: https://www.happier.com/delete-account
2 Enter your email address and password on that page
and click on Login.
3 Last step – Click on the red button: Delete my Happier account
This will have immediate effect.
A message appears that your account deletion is now in progress. You’ll be logged out automatically and your account will be removed. Mission accomplished!
Source (& thanks to): happier.com