💲How to make my product both bookable and buyable?

On your product page (on the Shopify dashboard, not on Cowlendar), you create a variant called "Buy it directly or Book an appointment?" with 2 options :

option 1 : Buy directly

option 2 : Book an appointment

Then on Cowlendar you click on "new service" and you only link the calendar to the "book an appointment" variant

So if your customer clicks on "Buy it directly" he will see the "add to cart button"

If he clicks on "book an appointment" he will see the "book now" button.