How to change add to cart text in woocommerce

For Single product page

Add this below code to your theme functions.php file

  //for  < 2.1
add_filter( 'add_to_cart_text', 'woo_custom_cart_button_text' );    

// for 2.1 +
add_filter( 'woocommerce_product_single_add_to_cart_text', 'woo_custom_cart_button_text' );  

function woo_custom_cart_button_text() {

        return __( 'My Button Text', 'woocommerce' );

}


For Product Category Page
Add this below code to your functions.php file

add_filter( 'add_to_cart_text', 'woo_custom_cart_button_text' );                        // for < 2.1

add_filter( 'woocommerce_product_add_to_cart_text', 'woo_custom_cart_button_text' );    // for 2.1 +

function woo_custom_cart_button_text() {

        return __( 'My Button Text', 'woocommerce' );

}