What is my tax identification number?
Your Tax Identification Number (TIN) is a unique number issued by the government for tax purposes. The number used depends on the country, and may be called something other than a Tax Identification Number (TIN) in your region.
When you add a country to your tax residency list in-app, you'll be shown exactly what number is needed.
You can read about each country’s TIN, or equivalent, on the OECD website.