With YITH WooCommerce Product Bundles you can create bundles with the combination of some products of your shop. You can assign an ad-hoc price to the bundle or a price given by the sum of the single elements contained in the bundle itself.
The integration between these two plugins will give you the ability to show the bundles in the invoice.
In order to make the plugins work together, you will only have to activate them both. For further detailed settings on the product bundles, you can check the documentation here.