Hello,
Product categories inherit the WooCommerce shop page number of items per row. To edit the shop page number of items per row go to Theme Options > WooCommerce > Product Catalog. Also, you can find some additional settings in Theme Options > WooCommerce > Shop > Shop page layout. Keep in mind that this affect not just product categories number per row but also products number per row if you enter the category because product categories does not have separate option for this.
All the existing settings for the shop page you can find in Theme Options > WooCommerce > Shop > Shop page layout and Theme Options > WooCommerce > Shop Elements > Categories.
Regards