In order for you to provide your tax information, your revenue need to reach the tax information submission threshold.
Active accounts need to reach $100 in order to qualify for a payment. Cancelled accounts, however, can be paid out if their unpaid revenue are greater than $10. Since we don't ever issue payments for less than $10, we don't allow publishers to provide their tax information until their revenue have reached this amount.
Once you've earned $10, you'll be able to enter your tax information.