If the account was not a Roth, just skip box 11. It will not matter.
If it was a Roth, enter the year that the account was first opened. This will only matter if you withdrew the earnings (or the entire account) and you are over 59.5.
In other words, for Roth accounts, the entire withdrawal will be tax-free if you were over 59.5 and the account was opened at least 5 years ago. None of this matters for traditional IRAs.
You should see a FACTA checkbox next to box 11. If not, select that it was not checked.
