QuickBooks Online lets you set up a payment method to accept payments from customers.
Both the credit card and bank transfer option will automatically appear in the Invoice page once the Online invoice is selected from the settings.
While there isn't an option to remove the credit card option, you'll want to modify the invoice template. Just uncheck this payment method so your customers can only use the bank transfer when they pay their invoices.
The following steps below will guide you through on how to accomplish this:
Go to the Gear icon at the right top.
Select Customer Form Styles.
Find the template, then click Edit under Action.
Go to the Payments tab, then make sure only Bank transfer is enabled.
I've added these handy related articles to learn more on how customers can pay what they owe:
If the issue persists, open an alternative browser available for you.
If you want to use your custom form styles for invoices, see this article for the steps: Import custom form styles for invoices or estimates. You'll find the Frequently Asked Questions section at the bottom of the page, and this lists some common issues you may encounter during the import process.
Do you need anything else? Feel free to post a comment below, and I'll be sure to get back to you.