here is code section 721
(a)General rule
No gain or loss shall be recognized to a partnership or to any of its partners in the case of a contribution of property to the partnership in exchange for an interest in the partnership.
(b)Special rule
Subsection (a) shall not apply to gain realized on a transfer of property to a partnership which would be treated as an investment company (within the meaning of section 351) if the partnership were incorporated.
(c)Regulations relating to certain transfers to partnerships
The Secretary may provide by regulations that subsection (a) shall not apply to gain realized on the transfer of property to a partnership if such gain, when recognized, will be includible in the gross income of a person other than a United States person.
so unless 721(c) applies there is no reporting requirement under 721
if it does here are the regs
https://www.law.cornell.edu/cfr/text/26/1.721(c)-3
https://www.law.cornell.edu/cfr/text/26/1.721(c)-6 - procedural and reporting requirements.
