FTIN
What is an FTIN?
Your tax number in your own country — for example a Chinese taxpayer number or a UK UTR. Form 5472 asks for it. It is not a US number.
FTIN stands for Foreign Taxpayer Identification Number. It is whatever number the tax authority where you live uses to identify you. Form 5472 asks for the foreign owner's, alongside the country that issued it.
You do not need any US number to have one, and you do not apply for it anywhere — you already have it if your country issues one. Where a country issues nothing of the kind, the form is completed to say so.
Watch out: An FTIN that looks like a US Social Security Number is worth a second look. If the owner really holds an SSN, this is probably the wrong filing altogether.