I can help you sort this out, @jaxemerson.
The additional tab allows you to assign a type to your customer. This is available in QuickBooks Online Plus and Advance.
If you're using one and you're unable to view the Additional Info tab, let's perform a few steps to isolate and resolve this concern.
- Try your browser's private window since it disables browsing history and cache.
- Google Chrome: Ctrl + Shift + N
- Mozilla Firefox: Ctrl + Shift + P
- Internet Explorer: Ctrl + Shift + P
- Safari: Command + Shift + N
- If that works, go back to your regular browser and clear its cache.
- Also, you can try a different browser, if available.
Meanwhile, you can read through this blog to learn more about everything you need and resources for getting started with QuickBooks Online: Your First Time with QuickBooks Online - Everything You Need for Successful Bookkeeping.
Please feel free to let me know how it goes as I want to ensure this is taken care of for you.