From the ‘General options’ tab, you can find the option to hide the product prices and Add to Cart button on ALL products.
You can choose to hide one or both options options, for ALL the products in your shop. That way you can show only the Quote button and let your users submit a quote request.
With the YITH Request a Quote plugin it is not possible to select on which products to show/hide the ‘add to cart’ button and price. You will need our YITH Catalog Mode plugin to manage showing/hiding the ‘add to cart’ button and price per product.