Dear member, you have not mentioned whether your question relates to the claim of maternity benefit under the ESI Act, 1948 or under the Maternity Benefit Act, 1961. In case you are not covered under the ESI Act, 1961, you can claim the said benefit under the Maternity Benefit Act, 1961 provided you are eligible for the same.
Procedure to claim maternity benefit
I think the procedure to claim the benefit under the MB Act, 1961 must have been explained in the Rules as framed by the appropriate State Government where you are residing. In case you are residing in Karnataka, I hope the Maternity Benefit Rules as framed by the Karnataka State Government will be applicable. For more details, you can get a copy of the same from any law-book shop in the area. So far as I understand, you are required to obtain a Medical Certificate on the prescribed form (as per said Rules) and submit your application/intimation or notice to your employer on the prescribed form. I think to certify from which date a woman is required to be absent from work due to confinement/miscarriage, etc., is a medical issue and is to be certified by the competent Medical Officer/Medical Practitioner as laid down under said Rules.
I think regarding all the above procedures, you can also confirm the position from the concerned HR/HR department of the organization where you are working.
With best wishes.