What do these codes mean when I see the results of an ACH run?

Please see the attached PDF’s on definitions of the different Codes. If you are getting C code these are warnings that the institution is processing the transaction but something needs to be corrected or it won’t go through next time. R codes will give you a reason why a transaction was returned.
NACHA Reason Codes
NACHA Return Status Codes
NACHA Correction Codes