How do I use CategoryName to specify a UFUNCTION “Category”, is there a specific file where I define the CategoryNames ?
The documentation has
* Usage: Category=CategoryName or Category="MajorCategory|SubCategory"
The categories are just parsed at build time. You can use any name you want, there is no table or list you need to edit.
UFUNCTION(BlueprintPure, Category="MyCustomCategory|MyCustomSubCategory") // The quotes are optional.
void MyMethod();