Change Add To Cart & BuyNow button text.php

<?php
add_filter('fluent_cart/product/buy_now_button_text', function($text, $data){
    $text = 'Purchase Now';
    return $text;
}, 10, 2);

add_filter('fluent_cart/product/add_to_cart_text', function($text, $data){
    $text = 'Add to your shopping';
    return $text;
}, 10, 2);