Functions using the get_text filter

get_text_filter.php

function custom_wc_translations( $translated_text, $text, $domain ) {
  if(is_checkout()){
    switch ($translated_text) {
      case 'Replaceble_text' :
        $translated_text = __('String to Replace', 'Domain');
        break;
    }
  }
  return $translated_text;
}
add_filter( 'gettext', 'custom_wc_translations', 20, 3 );