Miss. Code § 27-17-489
Any person desiring to avail himself of any of the exemptions provided in Sections 27-17-479 through 27-17-485, shall, before engaging in such business, file with the officer whose duty it is to collect the privilege tax, an application for the exemption certificate accompanied by an affidavit stating fully the grounds upon which such exemption is claimed. If the exemption be claimed on grounds other than a manifest visible disability, the above required affidavit must be accompanied by a certified statement from a county health officer, or the United States Veterans Bureau in the case of veterans of the World War, showing that the applicant is disabled to the extent of fifty percent (50%) as defined in Section 27-17-479. If fully satisfied of the facts and of the justice of such claim, the officer shall issue to such applicant a certificate of exemption which shall authorize such person to engage in the business therein designated for a period of one (1) year. The procedure above set forth shall be required in every instance for the continuance of such business during each and every year subsequent to that for which the exemption certificate was originally granted. Provided, that the tax collector before issuing any additional certificate shall require the applicant to show to his satisfaction that the gross income of the applicant for the preceding year was not more than nine hundred dollars.
Miss. Code § 27-17-489