MultivendorX supports WooCommerce taxes. So the admin can configure taxes from backend and vendors can select those tax classes while creating or editing the products. This document will help you out on how to configure the tax settings from the admin end.

Now, you can also let the vendor add product-specific tax. This document will help you out on how to configure per product tax: https://wc-marketplace.com/tech-blog/vendor-per-product-tax/