functions.php

<?php

function cart_notice() {
  if ( arunas_only_virtual_products() ) {
    return true;
  }
  $free_shipping_settings = get_option( 'woocommerce_free_shipping_settings' );
  $maximum = $free_shipping_settings['min_amount'];
  $current = WC()->cart->subtotal;
  $formatteddifference = wc_price( $maximum - $current );
  if (  $current < $maximum ) {
    echo '<div class="woocommerce-message">' . __('Get free shipping if you order for ', 'oxygen') . $formatteddifference . __(' more!', 'oxygen').'</div>';
  }
}
 
add_action( 'woocommerce_cart_contents', 'cart_notice' );
add_action( 'woocommerce_review_order_before_payment', 'cart_notice' );

function arunas_only_virtual_products() {
  $all_virtual_products = false;
  $virtual_products = 0;
  $products = WC()->cart->get_cart();
  // Loop through cart products
  $all_products = sizeof( $products );
  foreach( $products as $product ) {
    $product = wc_get_product( $product['product_id'] );
    if( $product->is_virtual() ) {
      $virtual_products += 1;
    }
  }
  if( $all_products == $virtual_products ) {
    $all_virtual_products = true;
  }
  return $all_virtual_products;
}