With the YITH WooCommerce Delivery Date plugin you can allow your customers to choose a specific delivery date for the products they purchase.
By activating both plugins, a new option will become available in the YITH > PDF Invoices & Packing Slips > General Options > “YITH WooCommerce Delivery Date integration”.
By enabling this option, the delivery date information will be shown in the packing slip pdf, like the example below:
For further details about YITH Delivery Date, please, refer to the official plugin documentation.