If you are not using ioby's fiscal sponsorship service you must provide proof of tax exemption. For most, that will be an Affirmation Letter or Determination Letter from the IRS. (Please note, state-issued letters are not accepted. Documentation must be federally-issued from the IRS.)
If you are a school, a religious institution, or a 501(c)7, proof of tax exemption will vary depending on your state and incorporation status. Please consult with your tax professional about appropriate documentation for your federal tax exempt status. If you have more questions or need further clarification, please reach out to your Leader Success Strategist at firstname.lastname@example.org.