Have you created an online store and you want the number of products that have been added to the cart to appear in the heading?

Hello,
how does the customer see the number of products in the cart?
For example, the customer chooses a product but does not complete the purchase, will see more products, then how does the customer return to the cart?
Can you tell me how to do that?
A shopping cart should appear on the menu to indicate how many products you have, but how do you do that?

Thank you for your attention

Friendly hug

Luis