Bloom uses Authorize.net as its payment gateway. You won't need to log into your gateway very often since Bloom and Shopify handle most of your payment, reporting and refund needs. Here are a few reasons why you might need to use the gateway:
Here is a link to log into your gateway. If you don't have log-in credentials, contact us.
For more information on how to use the Authorize.net gateway, here are few relevant links to our documentation: