Hi radha,
Good job on importing your invoices in the program. QuickBooks Online has several tools to ensure you don't start from scratch in your bookkeeping. I'll be happy to share more on this.
At the moment, there's no option available to import invoice payments in QuickBooks Online. While you can import invoices, manually adding the associated payments is the way to go to make sure everything is entered correctly. Here's an article to assist you with that: Record invoice payments in QuickBooks Online
Feel free to also check out our Apps menu to explore any third-party application that could better assist you with your task.
I hope this helps to clarify things for you! Don't hesitate to reach out if you have more questions.