Hi there, tparkcpl,
It could be a browser-related issue. Let's perform the recommended steps to fix and isolate this behavior.
You can start by using a private window and create an invoice from there. Browsing privately disables the cache from saving your recent accessed data. Hence, causing you not to be able to click the Product/Service field.
When that works, you need to clear the browser's cache to delete all data saved on this site. Also, use a supported, up-to-date browser to have the best and most secure experience with QuickBooks Online.
Follow the linked steps for your browser:
After clearing the cache, make sure to restart your browser. You can also clear Intuit-specific cookies from your browser. Check out this article for details steps: Clear cache and cookies to fix issues when using QuickBooks Online.
Let me know how this goes by commenting below. Just tag my name and I'll get back to you.
