Yes, admin can set number of days for vacation or when store will not be opened for the customers in Magento 2 Delivery Date Extension . Also additional notes can be displayed to customers to let them know about the store holidays.

Here are the few more resource to help you get most out of this Magento 2 Delivery Date Extension.

• How to Add Delivery Date to the Checkout Page in Magento 2 with Time
• How to Ensure Magento Product Deliveries with Delivery Date
• 3 Best Magento 2 Extensions to Offer Personalized Shopping Experience