Automatic Clearing House credit means depositing funds into an account and ACH debit means taking money from an account. While there is some charge for ACH credit option, there is a fee distributed for ACH debit transactions.
For debit, the department banks are authorized for the fund transactions. On the other hand, only the financial institutions are authorized for transactions of funds in ACH credit.
With ACH credit a person has the benefit of eliminating delivery of checks as funds are deposited automatically, minimizing security of checks. As for debit, a person can have the funds on a scheduled date, eliminate manual processing of payments, rid inaccurate checks, and reduce delinquencies of receivables.