Box 2a on your Roth 1099-R should be blank. This is the taxable amount of the distribution. Generally, Roth distributions are not taxable. If you have owned the Roth for more than 5 years and are over 59-1/2, those distributions will never be taxable. If you don't meet those qualifications, but are only withdrawing from your contributions, the distribution is also not taxable.
