Choose "Test" and use test card numbers to make sure your integration is configured correctly.
Ex: Use "4111111111111111" for a test Visa number, any three digits for a security code and any future date for an expiration date.
Be sure to choose "Live" to accept real payments.

You'll select this title from the list of payment gateways when you add this gateway to a form.

This must also be set in your merchant account. Click here for more information about creating your signature key.