How do I put back the number of days an invoice is overdue on the main invoice page
Welcome back to the Community. I trust that business is going well on your end. I'll be glad to guide you and share more info so you're on the right track with your work.
The feature you've requested isn't available in QuickBooks and I encourage you to send feedback about this to our engineers. To send feedback, click on the Gear icon and look for Feedback. New product ideas and improvements are influenced by users like you. In the meantime, I recommend looking into third-party apps. You can review the list of apps that can sync with QBO here: QuickBooks Apps.
Feel free to ask other questions. I'll be one message away in case you need additional support.