Miva Merchant supports a large number of payment modules and methods and the exact steps to configure each one varies. The general process looks like this:
In most cases, installing a payment module will add one or more tabs under > Payments. For example, if you install the Amazon Payments module, you'll see a new tab: > Payments > Amazon Payments tab
Some Payment Modules support a number of payment methods. For example, Authorize.Net supports American Express, Visa, MasterCard, etc. When you configure the Payment Module tab, you select the payment methods that you want. The exact steps to configure each Payment Module tab are described throughout this chapter.
3.1. You installed the Authorize.Net module.
3.2. In the Authorize.Net Payment Services v3.1 tab, you selected American Express, Visa, and MasterCard as the payment methods.
3.3. All of the payment methods that you selected will show up in the > Payments > Payment Methods Rules tab.
See To Edit Payment Method Rules.
3.4. If you double-click on a payment method, you'll open the Payment Method Rules dialog box. This dialog box has a number of settings that affect how the payment method works. The settings you choose here will be a store-wide default for all of your products.
You can also restrict payment methods at the product level:
Catalog > Products tab > edit product > Product tab > Payment Rules section.