In order to change the payment from monthly to annually or vice versa, you need to:
1. Click on your profile icon, it`s located in the lower-left corner.
2. Go to the "Billing" section. Then "Your plan". Here you can activate or deactivate "Annual payment" (-20% discount)"
5. And the last step - select your tariff plan and click "Activate plan".
And you are done!