Woo Button Text Changer can change woocommerce button text globally. You can change button name from WordPress admin panel. and also change the color, shape , and styles also special of related product remove from single product page.
VIsit: http://www.exclutips.com/plugins/woo-button-text/
The following are other recommended plugin for Woo Button Text Changer.
Woo Commerce https://wordpress.org/plugins/woocommerce/