The VAT number option is available to European country users.
You can request a VAT number change from your account from the users area at https://users.sonokinetic.net. Click on the “Edit” button and click on the “Change VAT Number?” link. It will ask you to enter a new VAT number prefixed with your current billing country code.
Submitting the VAT number change will open a support ticket. Our support staff will assist you to change the VAT number.