To remove the "On Sale" sale tag for all products, you just need to deactivate this option by uncheking the "Display an "On Sale" badge on the pictures of products that are on sale" box in the "Edit online store and checkout options" in your site editor. If you want to remove it for a specific product you would do that by removing the discount on this product, by unchecking the "This product is on sale" box for this product
How to remove the "on sale" tag for a product?
