WooCommerce Shop Global Discount let’s you set discount for all your shop’s products.
Discount can be fixed or calculated as percent from the price.
You can apply discount to all products or only to products that are already on sale.
Additionally you can apply discount only to products from selected categories. If option is not set, discount is applied to all products.
You can create multiple discount groups. For example this will help if you want to create different discounts for different product categories.