From the instructions:

Where To Submit Form 8985
Audited partnerships and pass-through
partners submit Form 8985 to the IRS by
fax at 888-981-6982, with or without
Forms 8986, as applicable.
Note. Electronic submission of Form
8985 will be required in the near future.
Until further notice, the form must be
submitted by fax.
AAR partnerships that are electing to
push out adjustments to their partners or
have adjustments that do not result in an
IU include Form 8985 with their AAR along
with Forms 8986.

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Where To Submit Form 8986
Audited partnerships and pass-through
partners submit Forms 8986, along with
Form 8985, to the IRS by fax at
888-981-6982.
Note. Electronic submission of Form
8985 will be required in the near future.
Until further notice, the form must be
submitted by fax.
AAR partnerships that are electing to
push out adjustments to their partners or
have adjustments that do not result in an
IU furnish Forms 8986 to their partners,
and include Form 8986 with their AAR
along with Form 8985.