@sakibxvz sorry to hear that.
Our vendor page is a taxonomy page just like the category page. So kindly check if the header footer are displayed correctly on the category page or not.
If that is displayed properly on the category page then contact your theme team and let them know that you are using a custom taxonomy page and their header and footer are not coming on that page and ask for their solution.
If your theme had been coded according to WooCommerce standards then there would not be any such issue with the header and footer on the store page. You can use any default theme like storefront.
But as it is not coming so kindly ask them how they add header and footer for a custom taxonomy page. If they need any help from us, let us know.