Can I link billable time entries to an invoice that has already been sent?

Yes, @Hirvin35, you can link billable time entries to an invoice that has already been sent. I'll go over some details and get you going.

After you send the invoice to your customer, you still have the option to edit it. Here's how:

1. Go to the Sales menu and select Customers.
2. Find the customer for whom you want to link the billable time entries.
3. Click on the customer's name to open their profile.
4. Look for the invoice in question and click on it to open it.
5. On the right-hand side, you'll see an arrow, click on this to expand the list of open timesheets. 
   
   
    
6. After selecting the billable time entries, save the changes.

You may also want to find out more about how to invoice your customers for billable expenses and timesheets.

I always have you're back if you have any other concerns managing invoices in QuickBooks. Leave your comment below and I'll surely get back.