I would like to know if a customer can enter and save their own credit card information into their profile in my QBO account? Or do I have to manually enter it?

Hello acschlereth,  

Thanks for connecting with us here. QuickBooks provides the flexibility you need to manage your business with ease. The program is equipped with a variety of features that make it easy to streamline your work and manage your valuable customers. 

Based on what you've described, the option is completely up to you. If you'd like for you customer to add their payment info by themselves, I'd recommend checking out this article here that shows you how to add a user to your account. Once you've added them as a user, you or them can follow these steps to save the credit card info: Click on Sales > Customers > click on the customer in question. Click Edit >  Go to the Payment and billing tab > Select Credit Card as the Preferred payment method or click Add new to add a new option (Note: Be sure to check off This is a credit card and then Save when you choose the Add new option). Click Enter credit card details. Enter the details, then click Save.

Give this a try and let me know if this info helps. I'm here to help. :)