On the Kalles demo, you see this feature on Pre-order products:
If you wanna achieve it for your store, kindly follow the instruction below.
From Kalles theme > Customize > Theme Settings > Product Page > Tick on the
2. Configure Estimated arrival date for Pre-order product
From Shopify Admin > Products > Open the product that you configured as a Pre-order product. You guys can configure follow my video below: