You got me here to help you add billable hours in QuickBooks Online, tgirard22. 

The Billable feature is only available in QuickBooks Online Plus and Advanced version. Also, adding billable hours through the mobile app is not an option. However, you can add billable hours using a web browser as a workaround.

Here's how:

1. Click the (+)New button.
2. Select Invoice.
3. Select the customer.
4. Under Add to Invoice, select the Billable expense, then click Add.
5. Click Save and close. 

If you're referring to adding billable time, you can follow these 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. Click Save and Close.

To learn more about billable expenses and time, check out these articles. It provides detailed instructions and guides on how:

• Enter billable expense.
• Enter billable time in QBO.

If you have any other queries, please post again to this thread. Take care and have a good one!