We can help you, but their name and the state where they are being held would be a good clue for us to get started :)
https://www.inmateaid.com/ask-the-inmate/how-do-i-go-about-getting-my-cousins-inmate-jail-registration-number-because-i-39-m-trying-to-finish-this-process-requirements-that-it-39-s-asking-me-for-in-order-to-complete-transaction-of-sending-money-to-her-etc#answer
Accepted Answer Date Created: November 19,2016