I can see how you want a field to be added to a bill. To make sure we can do this, I'm here to provide you with some information and guide you on how, kmepeco.

For now, the ability to add custom fields to bills is unavailable. In the meantime, you can continue using the memo field to add any useful information about your transaction. You'll want to go to our Customer Feedback page to check if a request has already been submitted. If not, you can send feedback to let our product team know how this feature helps your business.  Normally, implementing these requests will depend on the number of votes that we received. 

Furthermore, QuickBooks Online provides you the tools to create attractive, professional-looking invoices, estimates, and sales receipts. Learn how to customise the appearance and layout of your sales forms. I've added this article for your guide: Customise Invoices, Estimates, and Sales Receipts In QuickBooks Online.

Moreover, if you've already paid for a business expense, follow this article on how you can record payments toward a bill. Please check out this article: Enter Bills and Record Bill Payments In QuickBooks Online.

Feel free to let me know if you have any questions about a bill template. I'll be right here to assist.