Hi fy 23179fgv,

It's great to see that you're taking advantage of the time-tracking capability of QuickBooks Online. The Time-tracking feature will allow you to attribute time to the customer or project that the employee spent on the job. I can help you with adding the billable time from your timesheets to your invoices.

To add billable time to an invoice that has already been created just follow these simple steps:

1. Click on Sales from the left navigation menu.
2. Go to the Invoices tab.
3. Choose the invoice you'd like to add the billable time on to.
4. On the right-hand side, you'll see an arrow, click on this to expand the list of open timesheets, billable expenses, or estimates.
5. Click Add on the timesheet you want to add to the invoice.
6. Fill in the appropriate Sales Tax Code.
7. Click Save and Close

Your invoice will now include the time that you want to bill to the customer or project. This will mark the status of your timesheet as closed in your Sales Tab. 

If there's anything else I can help with please let me know. Have a fabulous day!