If it is a job (employment on salary), then in most cases, the notice period and exit are mentioned. If you are the HR, you should have the format changed.
Notice Period Guidelines
If no notice period is mentioned, then the standard notice period specified in the relevant act (factory, shop & establishment) as well as in Standing Orders (which always have a standard notice period) will apply. If it is not in either, then you will need to also check if there is an HR Manual (provided it was shown, communicated, and employees were given a chance to read and know it), then the notice period stated in that will apply.
Non-Statutory Notice Periods
For non-statutory source notice periods (e.g., in HR Manual), it needs to be a normal 30 days or what is generally acceptable in the industry. An excessive period would be rejected by the courts (if the matter went up there).