looks like that is a section, is that the case? so wouldn't be able to be added within another section, especially in the customiser..  would need to look into creating that functionality in a snippet perhaps

hard to tell how they are doing it, if not using an app

Yes, a whole bunch came through last nightcheck if you have a valid dmarc set up here DMARC Inspector - dmarciansee here for information about this and how to set it up correctlyShopify Help Center | Setting up your emailspecifically here Shopify Hel...

i dont know about how your site works etc but this person has added a dropdown...so you could incremenent 0, 0.5, 1, 1.5Solved: quantity selector increement 0.5 in product page doesn't update in cart - Shopify Community

If you are using the quantity field, this is not possible as that only accepts integers. please see here for some suggestions for dealing with this depending on your technical abilities/budget0.5 Increment in product quantity - Shopify Community