I am currently using the Presitge theme and I wanted to add a "Quick Add" button like this example here:
I have seen it done on this theme before, Im just not sure how to add it?
Please try this app : https://apps.shopify.com/collections-add-to-cart
otherwise customization is neded .
I am unsure whether the Prestige theme comes with AJAX ATC buttons for collection items built-in, it's worth contacting their support to double check. Anyhow, I'm afraid there are no simple copy/paste solutions for this specific case. It's a fairly complex requirement, it would require a developer to code and implement it into the theme.
Perhaps someone around here will be kind enough to devote their time to achieve this for you. However, if it's an urgent matter and you're after a quality solution, the best bet would be getting contacting a Shopify developer.