ManualDoc:W144

You may want to group similar products within the same category in order to get procurement and sales information summarized by each category.

Above is possible, due to the fact that "Product Group" is one of the "Dimensions" of Purchase and Sales Reports.
To learn more visit Procurement Analysis Tools and Sales Analysis Tools

Besides, each product category allows you to setup a different set of ledger accounts to be used while posting product related transactions such as purchase and sales invoices.
To learn more, visit Accounting tab below.