We have recently refreshed our branding across our offerings and changed the names of our pricing plans. If you have signed up before Aug 9, 2021, please click Previous plans to view your applicable plans.
We assure you that this change will not impact your product experience, and no action is required on your part.

This means that you're on the old Sprout plan, which is free for 3 agents forever. 

If you are looking to add more agents or upgrade to a higher plan, then you would have to enter your credit card details to pay for the extra agents based on the plan. 

To find more information on plans and features, go to http://freshdesk.com/pricing.