how to show product by tag as a filter via content module

Hi,

Are you talking about the "tag" option available in each product edit form just above the "published" option ?
I don't know how that would be possible. The tag system of joomla is quite difficult to customize for other needs than what it can be used by default.

Instead of using that "tags" setting, you could create a custom product field of the type "multiple dropdown". That would allow you to have a similar selector with that custom field on the product edit form.
And then, you could create a HikaShop content module to display all the products.
And finally, you could develop a small plugin implementing the onBeforeProductListingLoad event of HikaShop to filter the products of that module based on the value(s) selected in the custom product field:
www.hikashop.com/support/documentation/6...reProductListingLoad

So why not use categories for that ?
You can create products listing menu items and select the category you want in the "main category" setting of the menu item.
That way, the products listing will only display the products of that category.
Then, the vendor can select the category he wants the product to appear in in the "categories" setting of each product.
Is there a reason why this wouldn't work in your situation ?