Good day, Muhammed. Let's get this sorted out.

You might want to ensure your Progress Invoicing option is enabled. Here's how:

1. Click the Gear icon at the top menu bar, then choose Account and Settings.
   
2. Go to Sales, scroll down and enable the option for Progress Invoicing.
3. Hit Save and Done.
   

Once enabled, the box should show up when converting your estimates to invoices.
 

You can scan through the resource below. This will provide you tips about how the progress invoicing feature works: Set up and send progress invoices in QuickBooks Online.

I want to be your main point of contact, so please let me know if you have any other concerns or questions. Please know I'm ready to assist further. Have a good one.