Either it’s a Grouped product or a Bundled product, in both the cases we add the several products and sell them as a single product. But the basic difference is that, for Bundled product the sellers add products to the Bundle and also the custom options such as color, size etc. So that the customers can configure the Bundle product by selecting custom options before purchasing.
Whereas for the Grouped product there is no feature as such. The seller simply adds the products to the grouped product and the Grouped product will be available on the front end for the customers.
It totally depends on the requirement. If the sellers want their customers to customize the color, size etc of the Bundle product before the purchase then Bundle Product is the best solution. But in case you want to restrict your customers and don’t want them to customize the Grouped Product package, then you can go for Grouped Product.
If you have any issue, please feel free to add a ticket and let us know your views at https://webkul.uvdesk.com
You can visit the following links to get to know the Grouped and Bundle product creation in the marketplace-
https://webkul.com/blog/marketplace-bundle-product-for-magento2/
https://webkul.com/blog/magento2-marketplace-vendor-grouped-product/