secretary falsely accused me of fraud in email copying another manager. Work for government so it’s public record. I’m currently studying to be a cpa.

I presume you are asking if you can sue the secretary.   One of the elements of any lawsuit is damages. I am unclear what they are.   I do not know how you will provde that she is the one who did it.   Also there is the issue of collecting damages. Does she have any assets beside a residence, a car she owes money on, a salary as head of household protected from garnishment/   These are questions any lawyer who is considering handling the matter on a contingency basis would ask.