Dear MK,
In a limited company, the board of directors does not always have time to sign every appointment letter. The HR manager is responsible for signing appointment letters, and sometimes the CEO of the company may also sign them. However, HR has to issue many types of letters regularly, such as offer letters, increment letters, appreciation letters, confirmation letters, etc., and each time, the same person's signature should be there. Therefore, it is advisable for the appointment letters to be signed by the HR head or HR manager.
Deepika