Thanks for coming here, @prateekjain13.
Let me route you to the best help so you can launch your app that integrates with QuickBooks Online (QBO) at a smooth pace.
Concerning launching an application that will integrate into QBO, I recommend contacting the Intuit Development Team. You can work together with them for a better introduction to your app and lessen the technical issues during integration.
Also, they can guide you on why you need to URL to your app and what the things you need to perform before launching.
Additionally, feel free to visit this page to be in the loop on QuickBooks product updates: https://quickbooks.intuit.com/r/
Come back here, @prateekjain13. If you have additional questions about the integration of your app to QBO. I'll be willing to lend a hand. Have a good one.