List tickets API include credits?

Hello, I’m new here. I am implementing the Freshdesk API in my application. I am listing the tickets I have created, but I want to obtain the data of the person who created the ticket. For that, the documentation indicates that I should use the ‘include’ property. However, there is something I don’t understand about the credits: ‘Use ‘include’ to embed additional details in the response. Each include will consume an additional credit. For example, if you embed the requester and company information, you will be charged a total of 3 API credits for the call.’ What do you mean by credits? Is it an additional cost? Where can I see these credits? can someone help me please

My only guess is that they are referring to API call limits, but honestly, I have no idea.
I have looked over that documentation many times and never noticed that section. I just constrained my calls to the rate limits, and things worked well.