How do I apply to accept a new credit card type?
To find out what types of credit cards you accept, and to apply to accept new credit card types (like American Express or Discover) you should contact your Merchant Services Provider.
Once you have a new credit card type set up with your Merchant Services Provider, you should confirm that it is listed in your Authorize.net account.
Click here for the steps to confirm that a new credit card type has been registered in Authorize.net:
https://support.authorize.net/authkb/index?page=content&id=A383&actp=search&viewlocale=en_US&searchid=1396462805595
Once you have a new credit card type set up with your Merchant Services Provider, you should confirm that it is listed in your Authorize.net account.
Click here for the steps to confirm that a new credit card type has been registered in Authorize.net:
https://support.authorize.net/authkb/index?page=content&id=A383&actp=search&viewlocale=en_US&searchid=1396462805595
How do I apply to accept American Express?

American Express charges separate rates and fees and requires a separate application from other credit cards. Because American Express handles all of their own accounts, an American Express account is separate from your other credit card accounts.
To learn more about American Express fees, you can contact American Express at:
American Express Merchant Services:
1.800.528.5200
To learn more about American Express fees, you can contact American Express at:
American Express Merchant Services:
1.800.528.5200
If you decide that you would like to apply to accept American Express cards, you should reach out to your Merchant Services Provider for more information on how to manage this.