If you’re looking how to set the default product category in WooCommerce, you might think to look for a setting somewhere. After all, setting the default post category is found in Settings > Writing. But it’s even simpler to set than that.
To set the default WooCommerce product category, visit the product category page here: Products > Categories. Once there, hover over the category you want to set as default and click on the ‘Make Default’ link that appears:
While you’re there, might as well get rid of the incredibly unuseful Uncategorized product category. If it’s currently set as the default you will need to set another category as default first. Then simply hover over Uncategorized and click delete. Poof: