Hi
Normally you have to provide appointment letter, pay slip and relieving letter, offer letter is not that important and some companies now a days asking for For 16 issued by the employer for the last financial year. Even Copy is OK, most of the companies in their job application form they are ensuring a declaration from the applicant and beneath that the applicant is signing, the gist of the declaration is that whatever the information is provided by you is true to the best of your knowledge and not given any false information and in the appointment letter all are ensuring a clause that the information provided by you founds false the mananagement is having every right to terminate the services hence what ever information and documents provided by the applicant should be genuine, in this context even it is a copy also management is having every right to initiate action.
Mostly companies are doing the back ground check and on completion and correctness of the check only every employee is recruiting.
The applicants should be very careful and cautious in the above circumstances while providing the documents and information.
Regards - kameswarao