If you are requesting the Payeezy from FirstData - this is what you'll need to set up. "PAYEEZY GATEWAY WEBSERVICEAPI"
Step 1 : Login to https://globalgatewaye4.firstdata.com/
Step 2 : Select "Terminals"
Step 3 : Select the Terminal with a value below the Gateway
Step 4 : You're going to want to copy over the Gateway ID
Step 5 : Hit Generate by Password & copy over the supplied password generated.
Step 6 : Make sure to hit UPDATE