Hi,
After interview they will inform you that whether you are selected or not, If you are selected they will mail you offer letter along with a mail regarding documrnts which is required for joining.After that they will call you for document varification after that you can join. On the day of joining they will give Employee Id No as well as other formalities such as induction ,,PF,ESI Enrollment,Bank Account Opening .
Regards
Amrita