A merchant account is an account set up through a credit processing company or a bank that accepts and processes debit and credit card orders.  You cannot accept payments by any of the major credit card brands without a merchant account.

Merchant accounts can be obtained through an acquiring financial institution or the merchant services department of a bank through a formal application process.  In this process, your financial institution will assess your credit to determine if your company is eligible.  Therefore, merchant account providers usually require copies of your financial statements and/or an extensive business plan outlining your sales ventures.