Depends. But probably two 1099-INT forms
1) For the i-bond you cashed, you should create a 1099-INT form the US Treasury, and put the interest in box 3.
2) For the Treasury Bills, you "probably" hold those at a brokerage. IF so, you need to get the 1099-INT form that brokerage and either import it, or enter it manually. It may have other $$ in other boxes that also need to be filled in. Those held there can be summed together and not entered individually.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
