If I want to put my customers credit cards on file for regular invoice payments, is there a way the customer can do this themselves without giving me the card info?

Thanks for posting here, Sunny.
 

I understand how important it is for you to allow your customers to fill in their credited card information in QuickBooks Online (QBO). However, this feature is not yet available.

With this, I recommend submitting feedback to our Product Developers so they can consider adding this feature in future updates. Here's how:
 

1. Hit the Gear icon and select Feedback under Profile.
2. Enter your product comments and suggestions.
3. Click Next to submit.

In addition, I also added this article to help you in updating the customer's billing information QBO: Edit a customer's credit card information in QuickBooks Online.

If there's anything else that I can help you with, please let me know in the comment section below. I'm always here to help. Take care.