If you would like to ask your customers to select a date for shipping before they checkout, then follow the instructions below:
1. Click Settings within the Store Pickup and Delivery app
2. Click on the Shipping option:
3. Scroll down to the Date picker section and click Enable:
4. Check the days of the week that you offer shipping
5. Click Save
Please allow a couple of minutes for your changes to be updated within Shopify.
Now when your customers visit your shopping cart page and select Shipping, they will be asked to choose a date before they can proceed to the checkout.