For most Carriers, the email address and telephone number are mandatory fields.

In case they're not present you can remove the check of mandatory fields from My Profile > Preferences > Carriers preferences by unchecking the option "Check order data during shipping."

The system will no longer ask you to insert the mandatory field (such as phone number), but please note that if a specific Carrier is requesting the field to be present, the shipment will go into error.

In that case, you will need to insert a fake phone number or email address to create the shipping label.