Hi there, @janie9. Yes, you can still add a billable expense to an invoice even if you created the invoice before the bill came in.
When you enter the bill and mark it as billable to the customer, it will appear as an unbilled charge that you can add to the existing invoice.
To add it:
- Open the invoice you want to add the billable expense to.
- Select Manage, then choose Suggestions.

- Review the Suggested transactions and click add to link the billable expense.

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