A tax audit is an investigation of an organization or individual tax return that verifies that the financial information is being reported accurately. A tax audit can be done by a qualified Chartered Accountant (CA) with a Certificate of Practice (COP) and who is in full-time practice. The tax auditor should submit the report in the prescribed form i.e. Form 3CA / Form 3CB. To get more information regarding the section 44ab of income tax act, do check out Tax Guru.