POWr eCommerce allows you to add shipping fees to Products in two ways: Per Order and Per Item.
Charge a single fee for an entire order, no matter how many items are included. This is good for lightweight products that don't cost much to ship.
Go to Content > Shipping > Toggle on Shipping Fee Per Order and enter a shipping price. This will disable all Per Item shipping fees.
Charge a different fee for each product individually. This is good for heavy products, or products with very different shipping costs.
Disable Per Order shipping. Then go to Content > Open the product you wish to add a Shipping Price to > Click Pricing and enter the amount you would like to charge to ship that item.