The Reservation feature is not available for the PWA (Progressive Web App) application type/platform. This article presents a workaround to create the functionality of the Reservation Feature for your PWA by the use of the Website Feature.
You just published successfully your web app, but you noticed the Reservation feature does not appear on the list of the available features.
You can use external web services that offer this function and then integrate them into the app through our Website feature. Please check the How to Build the Website Feature KB article for more info on the feature.
You will be able to use similar functionality as the one the Reservation Feature provides on your Progressive Web App.