We can add a delivery date selector in WooCommerce Checkout with the following snippet.
You can customize the calendar as per your requirements with CSS.
This is how it looks in the orders section.
How to add this snippet?
You can add this snippet to your child themes functions.php , We don't recommend adding code to your main theme if its not developed by you. Otherwise you can use a simple plugin https://wordpress.org/plugins/code-snippets/
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