Hi there, @radar-9628. 

QuickBooks Desktop has a great feature for managing reimbursable expenses. I'd be glad to go into further depth on this.

You can turn on the Billable Expense feature to track the expenses you incur on your customer's behalf when you perform work for them. This way, your customer can reimburse them when they receive their invoice.

Here's how:

1. From the Edit menu, choose Preferences.
2. Select Time & Expenses.
3. Go to the Company Preferences tab.
4. In the Invoicing Options section, check the Mark all expenses as billable option.
5. Enter the Default Markup Percentage. You can leave this blank if there isn't a default percentage for the markup.
6. From the Default Markup Account drop-down menu, choose the correct account. If you don't have one yet, you can always scroll up and select Add New to quickly create a markup account.
7. Click OK.

Then, follow these steps on how to create a check and bill it to the customer:

1. On the Home page, in the Banking panel, click Write Checks.
2. In the Write Checks dialog box, from the Bank Account drop-down list, select the account to write the check on.
3. From the Pay to the Order of drop-down list on the check, select the vendor to pay.
4. Go to the Expenses or Items tab. Enter all the necessary information.
5. Enter the name of a customer or job in the Customer:Job field.
6. Mark this expense as Billable.
   
7. Click Save & Close.

After that, link the billable expense to your customer's invoice to reimburse the cost.

1. Go to the Customers menu, then select Create Invoices.
2. Select the customer or job that you entered on the bill.
3. On the Billable Time/Costs pop-up window, choose Select the outstanding billable time and costs to add to this invoice.
4. Go to the Expenses or Items tab.
5. Mark the expenses or items that you'd like to add.
6. Click OK, then Save & Close.
    

Once done, you can enter the payment once the customer pays you for the invoice.

Keep in touch with me here should you need further assistance in recording all these. I always got your back. Thanks for reaching out, wishing you and your business the best.