This only applies if your account has the Plan module.
Step 1:
Go to the ‘User’ tab and select ‘Subscriptions’ for the user whose subscription you want to manage.
Step 2:
Select ‘Add Subscription’ and select the plan you want to add. Optionally you can set this when the plan expires.
Step 3:
Select ‘Save’ to save the changes. You can also unsubscribe a user from a plan by clicking on the ‘Unsubscribe’ button and clicking ‘Save’.