@WillSun
You do not have to file a partnership return (Form 1065) if you do not want to go that route. Per Section 301.7701-1(a)(2), mere co-ownership of property, even if rented, does not create a separate entity.
As a result, you can each report your share of the income and expenses on your own individual income tax returns.
See also Rev. Proc. 2002-22: https://www.irs.gov/pub/irs-drop/rp-02-22.pdf
Similarly, mere co-ownership of property that is maintained, kept in repair, and rented or leased does not constitute a separate entity for federal tax purposes.
