The inmate is notified that they have money in their trust account by their counselor or through the internal communication system (i.e.Trulincs in BOP)
https://www.inmateaid.com/ask-the-inmate/will-the-inmate-know-that-he-had-money-to-make-a-phone-call-or-do-i-have-to-call-up-there#answer
Accepted Answer Date Created: July 10,2019