No, once a non-profit is incorporated, they will need to apply for recognition of exemption from the IRS. Tax exempt means that the nonprofit will not pay taxes to the federal government, and any donors can take a tax deduction for their donations to the organization.
Once your organization receives the determination letter from the IRS recognizing it as a tax-exempt organization, most states like New York, require that you register with the state’s Attorney General to be recognized as a charity in good standing.