Since you live in Arizona, which is a community property state, you can report your business as either a qualified joint venture or as a partnership.
See this IRS website for a qualified joint venture and how to report - https://www.irs.gov/faqs/small-business-self-employed-other-business/entities/entities
A Qualified Joint Venture requires you each to report your income and expenses on separate Schedule C's which are included as part of your personal tax return, Form 1040.
A Partnership tax return using Form 1065 is separate from your personal tax return and the complexities for completing and filing can be onerous.
See this IRS website for a Form 1065 - https://www.irs.gov/forms-pubs/about-form-1065
