Customs in some countries require your Tax ID to be printed
on the commercial invoice. If this is your case, the warning will
be displayed on your account when selecting shipping method for the
package.
To enter your Tax ID to your profile, please login to your
client account, show “Your Shipito and Home Address”
section, and click “change address” link.
In the form, the Tax ID field is displayed. Enter it there,
and click “Save Address” button.
After this, your Tax ID should be saved, and you will be able
to ship using the shipping method which requires Tax ID to be
entered.