Hello, appletreeconstru.  

Thank you for reaching back to us. Let me share some insight about what categories is in products and services. In QuickBooks Online, categories are used to classify products and services (usually represented by items) your company sells to customers. It allows you to create and edit categories that sync with your QuickBooks Online account. 

For more information on using Item Categories within QuickBooks Online, please refer to their help center article Introduction to Categories in Products and Services.   

If there's anything else that I can help you with, please let me know in the comment section down below. I'll be always around ready to help.