After the person appointed or confirmed as succession representative has qualified by furnishing the security required of him by law, and by taking his oath of office, the clerk shall issue to him letters of administration or letters testamentary, as the case may be.
These letters, issued in the name and under the seal of the court, evidence the confirmation or appointment of the succession representative, his qualification, and his compliance with all requirements of law relating thereto.
La. C.P. § 3159