Hi there,
Thanks for taking the time to reach out to us here. I'll be happy to share more info about QuickBooks so you can continue being amazing at running your business.
QuickBooks Online makes it simple to integrate other payment processors into your account. You'll have to use one of our third-party apps which you can find on http://www.apps.com. You'll just have to search for the payment processor's name and select the one that best suits your needs.
Let me know if this info helps. I'll be on standby in case you have other questions. Otherwise, enjoy the rest of your day.