How can I add an edit button on the cart page?

Follow the steps below to show an Edit button on the cart item:

Setup

In the app, navigate to the "Settings" tab.  

Enable the "Auto add cart item edit button" setting:

The edit button will open the product page again and pre fill all the option values based on the cart item:

When the customer adds to cart again, the item will be updated in place:

Note: Item update is only supported if the product variant is not changed.  

Modal

You can also enable the modal setting to show a modal window to let the customer decide if the item should be updated or if a new item should be added.

Translations

The translations texts for the edit button and the modal window can be found here:  Custom language translations

Manual theme setup

To provide your own edit button visit the related article below.