on return or return information (as defined in section 6103(b)) available to the Secretary, that such taxpayer may be eligible to claim such credit and a refund for such taxable year. (2) Notice Notice provided under paragraph (1) shall be in writing and sent to the last known address of the taxpayer. . (b) Effective date The amendment made by this section shall take effect on January 1, 2021. IV Ensure Taxpayer Access to Competent Tax Return Preparers 401. Regulation of tax return preparers (a) In general Section 330(a) of title 31, United States Code, is amended— (1) by striking paragraph (1) and inserting the following: (1) regulate— (A) the practice of representatives of persons before the Department of the Treasury