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Before a tax preparer can begin work, they must also meet state and federal requirements. First, apply for a PTIN by submitting personal information (including your social security number) and a previous year's tax return. This can be done online at http://www.irs.gov. Getting a PTIN will register you as an "unenrolled preparer," granting you the minimum level of clearance to prepare federal taxes. Note that this application will require to disclose and explain any felony convictions or problems with your tax obligations. CPAs and tax attorneys must obtain a license in the state they plan to work in. The education and experience requirements to sit for the licensing exam vary by state, so check with your state's board of accountancy for more information. When you've met the requirements, prepare and register for the exam. You must pass the exam in order to receive your license.

Summary:
Obtain a Preparer Tax Identification Number (PTIN). Become licensed, if necessary.