The IRS will allow tax preparers to e-file Schedules K-2 and K-3 starting this March.
Schedule K-2 and Schedule K-3 are new for the 2021 tax year. Tax professionals with items of international tax relevance must report them on Schedules K-2 and K-3 if they file Forms 1065, 1120-S or 8865.
E-filing capability for Form 1065 will start on March 20. See the IRS instructions.