Generally, churches do not have to file tax returns. However, a church will have to file a return and may owe income tax if it has "unrelated business income."
https://www.irs.gov/charities-non-profits/churches-religious-organizations
https://www.irs.gov/charities-non-profits/churches-religious-organizations/filing-requirements
https://www.irs.gov/charities-non-profits/annual-exempt-organization-return-who-must-file
