QuickBooks Online: Is there a way to show the customer's name in the Bill to window?

Yes, there is, mariarosak-amtel.

I'm happy to show on how you can make the customer's name visible in the Bill window. We can follow the steps below to get this done.
 

First, let's turn on the Track expenses and items by customer and Make expenses items billable from the settings.
 

1. Go to the Gear icon.
2. Select Account and Settings.
3. In the Expenses tab, turn on the  Track expenses and items by customer and Make expenses items billable.
4. Click Save. Then, Done.
   

Next, add the customer's name when creating a bill.

1. Go back to the QuickBooks Home page, and click +New.
2. Select Bill.
3. Select customer in the line item.
4. Click Save.
   
   

Also, we can run the Transaction List by Customer report. Then, we can customize this report to show only the Billable Expense Charge for each:

1. Choose Reports on the left panel.
2.  Enter Transaction List by Customer in the search field. 
3. Enter a Date Range.
4. Click the Customize. Under Lists, set the Transaction Type to Billable Expense Charge. You can add other details you need.
5. Hit Run Report.

Here are the articles that you can check for additional details about billable expense and personalizing reports:

• Enter billable expenses.
• Customize reports.
• Memorize reports.

There you go. Let me know if you have more questions about recording customer's information, transactions, and any other QuickBooks concern. I'm always here to help you figure them out. Take care always.