Admin can purchase the “Delivery Date Scheduler” as an add-on to provide the date and/or time selection to the user during the checkout of the order.
If you have purchased the add-on, you must have AppJetty’s Delivery Date Scheduler extension configured from the Magento backend. For that, navigate to Stores -> Configuration -> MageMob App Builder. 
Enabled: Select Yes to enable the “DDS support with the App builder”. AppJetty Deliver date module is also installed and enabled.
Delivery Date and Time Selection Label: You can decide the selection of the delivery date and/or time.
Frontend (App Builder app)
By clicking on the “Delivery Date and Time Selection”, the customer can select their desired date and time when they want to get the order. The customer can see the available dates on the calendar.
The customer can add specific instructions regarding the delivery and can opt for the Call option. 
Note: Your customers will get details and date/time selection view based on the configuration from the delivery date scheduler by you (admin).