One of my invoice is missing and cannot be found In the reports . How to I find what happened to the invoice . Its not found in the void list also

I've got few troubleshooting steps to help you look for the missing invoice, @userchetna.

Making sure you've recorded your sales transactions is necessary to monitor your business growth. In this case, let’s look at every corner of your QuickBooks Online (QBO) program to find the invoice. Since the invoice won't display on the report, let's now review the Audit Log to see any activities involving the missing transaction. Here's how:

1. Go to the Gear icon.
2. Choose Audit Log.
3. Select the Filter button and click All Users.
4. Input the date range and choose Transactions under Events.
5. Click Deleted/Voided Transactions in the Show: field.
6. Then, Apply.
7. If you see that the invoice was deleted, take note of the details so you can recreate it. 

You can also check your customer's transaction list to look for the missing invoice. Let me guide you on how:

1. Navigate to the Sales menu and choose Customers.
2. Click the customer's name where the invoice is allocated.
3. Once opened, click the Filter button.
4. Select All Invoices in the Type drop-down and enter the date range.
5. Once done, click Apply. 

QuickBooks also makes it possible to personalise your sales form to reflect more of your business identity. For the detailed guide, please check out this link: Customise invoices, estimates, and sales receipts in QuickBooks Online.

If you need further assistance finding the missing invoice, feel free to post a reply below. I'm always here to help.