Codes 1 and M are two separate codes. Enter each one separately.
Since you will be unable to come up with the money to be able to roll this distribution over, this distribution is taxable and, if you have no exception that applies, to a 10% early-distribution penalty. If you were able to come up with the money, the code M on this 2020 Form 1099-R indicates that you have until the due date of your 2020 tax return, including extensions, to come up with the money and roll over any or all of this distribution.
