Auto Update total Items in the cart

I have a custom Cart Button on Header →

<a href="" class="anchor_button7">
                    <img src="<?php echo get_template_directory_uri(); ?>/img/svg/shopping-cart_2.svg" alt="">
                    <span>Cart</span>
                    <span class="item-count cart-item-count">1</span>
                </a>

But I want that this “1” should automatically update instantly in real time based on the total # of items added.