A file formatted to NACHA specifications, which contains instructions for transferring funds between accounts. payroll file that is used to make direct wage deposits to employee accounts. Extended Definition. A file created in a NACHA (National Automated Clearing House Association) format is a NACHA file. It is used to transfer funds electronically. In the context of payroll, a NACHA file is used to deposit funds directly to employee accounts. NACHA is the industry watchdog of the ACH (Automated Clearing House) Network, which provides a secure network for electronic movement of funds across accounts.