Hi,

The Product category under the General info tab is used to define the hierarchical classification of the product within the system as you can see in the following example,

based on this category you can filter the product easily as shown below,

Whereas the Categories under the sales tab in the product config is used to categorise the products in the e-commerce as shown below

You can create new e-commerce category from website -> e-commerce -> e-commerce categories

This product on the website can be chosen from the category and will be like this

Thanks