Hello
Many companies have different procedures. however, I would like to deal with the legality of these two letters.
Let us start with the first and foremost issue of any employment......an employment is contract between the employer and the employee.
Start with this fundamental.
When an offer letter is issued with all terms covered including date of joining and specifying that the letter shall be returned within a stipulated period, it is the first step of the contract.
Then the employee signs the letter , hands over the same to the employer and says that he would join within the stipulated time, the contractual obligation begins for both parties.In fact the employer can not withdraw the offer and the employee can not avoid joining. In fact if an employee does not join, legally the employer can sue him for breach of contract.
An offer letter duly agreed by the employee completes trhe process of contract and hence there is no need for an appointment letter.
Consider an offer letter does not say anything about notice period and the appointment letter talks about notice period, then the employee can say that he was not told about the notiuce period before he resigned from his previous job and hence he can not accept the same, his plea will be upheld by any court.
Hence it is essential that offer letters are exahustive, and the organisation must get it duly signed.
If thius process is in place, then there is no need for an appointment letter. In fact, I do not advise two letters as the terms in the appointment letters can be questioned
Siva