How can I customize the vendor page template?
If you want to customize the vendor page via HTML or CSS, the first thing you need to know is that the base template used by vendors is archive-product.php, which is the same one used on the Shop page.
This is why all of the changes you are going to make on this template will be applied to the store as well.
If you want to create a custom template for the Vendor taxonomy page, you can do it by using the WooCommerce template hierarchy.
WooCommerce allows you to use custom templates specifically created for taxonomies. To do this, you need to create a file named taxonomy-yith_shop_vendor.php and copy it into the "woocommerce" folder in your theme.
In this case, the plugin will use this template instead of the default archive-products.php one.