Please explain the reason why you are asking the question if you want a more accurate answer.
Notice Period in Employment
Generally, the company decides how many days of notice it needs in case of separation (resignation/termination) and puts it in the appointment letter or in the HR Policy, and informs the employees. However, they must agree to the change; otherwise, it has no validity.
Referencing Model Standing Orders
If nothing is specified, you need to refer to the Model Standing Orders of the state where you are based and follow that as a benchmark.