Lulu Direct requires a valid phone number to be included with the shipping address when an order is created. By default, adding a phone number should be a required field in the WooCommerce checkout. 

If you find that the phone number field is not in your checkout by default, F4 Shipping Phone and E-mail for WooCommerce is a free plugin that has been known to resolve this issue. If a phone number is not included with the shipping address, we will automatically use the billing phone number that the customer provides.

To use the plugin, first install and activate the plugin on your WordPress website. Next, navigate to the WooCommerce Settings page. Select Accounts & Privacy, then scroll down to Phone and select Required.

Finally, scroll down to the bottom of the page and click Save Changes.