When two or more people hold property jointly on a deed, generally it is an concurrent estate.In concurrent estates, one party may be able to rent the property without the other party's knowledge, both will generally have the right to share in the rent income. However, the parties' rights may depend on the individual's mitigating circumstance.
Generally each of you would report your proportional share of the rent income and rent expenses on your individual income tax returns.
However a written agreement may have a different % allocation [ownership basis is not effected] if one co-tenant owner does not wish to actively participate in selection of tenants and managing the property.
A written agreement is also helpful if ever audited.
