Let me add insight into adding more than 400 words for payment details and footer sections in custom form styles in QuickBooks Online. Please know that we value customer feedback and use it to improve our services. I would be happy to pass your insights on to our software engineers so they can review your suggestion and consider it for future product updates. 

Here's how to submit feedback in QuickBooks Online:

1. Select Settings ⚙, then Feedback.
2. Enter your comments or product suggestions.
3. Then select Next to submit feedback.

Your valuable feedback goes to our Product Development team to help improve your experience in QuickBooks Online. You can track feature requests through the QuickBooks Online Feature Requests website.

Additionally, here are some articles that can help you receive and record invoice payments. You will also learn how to convert a customer overpayment or credit into a tip in QuickBooks Online:

• Record invoice payments in QuickBooks Online
• Record an invoice overpayment as a tip

Keep me posted if you have any additional questions regarding customizing your sales transactions or any QuickBooks-related concerns, @Paul. I'll be right here to help. Keep Safe!