In QB Esentials, how can I associate an expense that is an AP to a specific client?

The option to assign billable expenses to specific clients is only available in the Plus and Advance editions of QuickBooks Online (QBO), info2290.

Since you're currently using a different version, you may consider upgrading your plan to either the Plus or Advanced edition to gain access to this feature.

If you choose to upgrade your plan, you can proceed to the steps below on how to set up your billable expense:

1. Navigate to the Gear icon in the upper right side of your screen, then choose Account and settings.
2. Select the Expenses tab.
3. In the Bills and expenses section, click Edit.
4. Enable these three options:
   • Show the Items table on expense and purchase forms.
   • Track expenses and items by customer.
   • Make expenses and items billable.
5. Complete any necessary details.
6. Select Save, then Done.

Next, you'll want to follow steps 2 and 3 of this article for you to be able to record and assign a billable expense to a certain customer: Enter billable expense.

Please let me know in the comments if there's anything else you need help with.