Investors & landlords

Rental income is always passive income, assuming the property was Not used as a home.  Or you have a business which has rental properties then you report the business income and expenses on Schedule C.

Otherwise, you enter the rental income and expenses on Schedule E.

 

IRS Publication 527 Residential Rental Property (Including Rental of Vacation Homes) - https://www.irs.gov/pub/irs-pdf/p527.pdf