title: How to update shopping cart QTY
body: <p>I am making a shopping cart lie this pic I attached</p>
  
  <p><img src="https://i.stack.imgur.com/r5LFY.png" alt="enter image description here"></p>
  
  <p>The sum of the product is depent on the buyer
  my question is how can I press update button to update all QTY of  the product?</p>