Here is a handy Elementor extension that lets you add a purchase button for a specific product anywhere on your website. The Ader comes with 2 widgets that you can put to use without having to write a line of code. You can customize margin, padding, alignment and other settings for buttons.
This plugin is designed for WooCommerce. It supports simple and variable products. It has a responsive design and works with Font Awesome Icons. You get 5 templates to get started fast and can customize the buttons with a few click. Ader plays well with right to left languages too.