Thanks for getting back to us, RyanC3PO.

Allow me to join this thread and provide clarification about adding billable expenses.

The billable expense feature is only available in QuickBooks Online Plus and Advanced. You can use this article as an additional reference: How to Enter Billable Expenses.

To be able to avail of the said feature, you might consider upgrading your account to a higher version.

 Here's how you can upgrade your QBO subscription:

1. Click the Gear icon on the top menu.
2. Select Account and Settings.
3. Choose the Billing & Subscription menu.
4. In the QuickBooks Online section, click Upgrade. If you don't see it, you’re already using the plan with the most features.
5. Choose the plan you want, and click Upgrade.
6. Confirm your payment information and click Save.

Keep your post coming if you need more help. Have a great day!