[Bug]: Agent Transaction entities are not documented

[dmohns]

Preflight Checklist

• I have read the Contributing Guidelines for this project, if it exists.
• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for a feature request that matches the one I want to file, without success.

Expected Behavior

The documentation should explain all entities involved in Agent Balance.

Actual Behavior

The following questions are not answers

• What is an agent charge? How are they getting created?
• What is an agent receipt? And what is the difference from a charge?

Steps to reproduce

see above

What operating system(s) are you using?

macOS

Additional Information

No response