Good day, @Cmccourt.
QuickBooks Online (QBO) helps you manage and view all parts of your business, all in one place. Our general articles provide guidelines to easily track labor costs, payroll, inventory, income, and expenses.
With regards to specific books or guides on when a purchase is considered a business expense, I'd recommend reaching out to the IRS. This way, they can provide the right answer to clarify the concern.
You can contact an IRS customer service representative by calling the number listed in this link: https://www.irs.gov/faqs/irs-procedures/refund-inquiries/refund-inquiries-20#:~:text=Contact%20an%20...
Also, please reach out to your accountant for proper assistance in handling your books. This way, we can ensure that they're aligned with the IRS guidelines.
Moreover, you can check out this article from the IRS webpage: Publication 535 (2021), Business Expenses. This discusses common business expenses and explains what is and is not deductible.
Should you have any follow-up questions or concerns, don't hesitate to post again here in the Community or leave a comment on this thread. Take care and have a good one.
