You can use this extension for delivery date, Delivery Instructions and Delivery Date extension. It allows customers to enter "delivery instructions" or "order comments", "delivery date" and "delivery time" during checkout. This information gets saved against order which can be viewed in Magento admin panel under delivery instruction section.
The following link https://www.scommerce-mage.com/magento-2-delivery-date-and-instructions.html would be useful.
