Entering an expense that clients reimburse me for

Hello there, @PSFS. 

Welcome and thank you for posting here in the Community. I can share some information regarding expense transactions in QuickBooks Online.

You can follow the steps below:

1. Click the New (+) icon to bring up the transaction menu page. For Category under Vendors, choose the Expense tab. 
2. You will now see the Expense Window. Select a Payee for the expense. If it’s a new payee, you can enter their name in the field and click Add.
3. The next step is to choose the account where you get the money for this expense. 
4. Next, enter the Payment date.
5. After entering the date, enter the Payment method for this expense.
6. Choose a category for this expense. Under the Category section, choose the account category from the chart of accounts. For the new expense category, you can type in the category name in the Account field and click Add new.
7.  To be more detailed with your purchase, you can add more information in the Description.
8. You can also add notes in the Memo field for additional information for more details regarding the expense.
9. Enter the amount of the expense in the Amount field.
10. Click Save and New to save this expense and start another one, or Save and Close. 

You can check this article for your reference: Enter and manage expenses in QuickBooks Online.

 Please know that you can always post a comment here in the Community whenever you need guidance or information. We are always here to help you. Stay safe. God bless. 

I could be wrong here, but I'm going to go out on a limb here and say that @PSFS already knows how to create an expense...

As usual, a stellar answer from the QuickBooks team though - If I had zero intuition, I could still easily create an expense by following these easy steps. You should get a raise, seriously!

@LollyNino_C  notice that they added "that clients reimburse me for" on the end of the question. If they wanted basic instructions on how to enter an expense, it would make sense to just ask, "How do I create an expense?" Based on the fact that they added something extra, one could infer that something extra should be added to the answer, beyond the basic instructions for people who have never used a computer.