The Automated Clearing House (ACH) is an electronic network for financial transactions. ACH processes large volumes of both credit and debit transactions which are originated in batches.
ACH credit transfers include direct-deposit payroll payments and payments to contractors and vendors. ACH debit transfers include consumer payments on insurance premiums, mortgage loans, and other kinds of bills. Businesses are also increasingly using ACH to collect from customers online, rather than accepting credit or debit cards.
Debit transfers also include new applications such as the Point-of-Purchase (POP) check conversion pilot program sponsored by NACHA. FedACH is the Federal Reserve's centralized application software used to process ACH transactions. Both the government and the commercial sectors use ACH payments. The Electronic Payments Network is the only private sector ACH Operator in the United States.
ACH standards for automatic clearing house. In modern usage it is more common to encounter the terminology EFT (electronic fund transfers).
These terms are not quite synonymous:
All refer to a mechanism by which banks are able to transfer money directly from one account to another (held by a different party) at the request of the owner of the first account. A transaction charge may be levied by the bank for providing this service. Transfers between banks within different countries are more complicated, and usually attract larger fees as well as being more restricted.
Many online banking services allow users to conduct small transfers of this type automatically, often hidden within an option such as "make a payment". Internet-based services for conducting international transfers can be found easily by searching for suitable terms using google or similar.
The difference is essentially that ACH and BWT (bank wire transfer) are both subsets of EFT. Typically, BWT take place the same day that they are initiated, whilst ACH-based transfers can take a longer period (typically up to three days).
ACH = Automated Clearing House. It is a type of electronic funds transfer between two entities' bank accounts. It is typically used for payment processing. A wire transfer is an electronic funds transfer directly between the accounts. Wire Transfer is simply a generic term whereas ACH is a more specific type of wire transfer.
Another way to think about ACH is that it is tied more specifically to a business transaction. So, if you receive your paycheck through direct deposit, that is an ACH wire transfer of funds to your account for the purposes of payroll. The payroll is the transaction.
Anyone can perform a wire transfer of funds. You can go to your bank to perform such a transfer. It requires authorization to do so. But, you cannot perform an ACH transfer between two individuals.