When to make a claim on group insurance?

Health insurance policy provides cost of expenses incurred towards treatment for any illness, sickness or a disease. A group can purchase the insurance for its members/employees under group health insurance. 
A claim under a group health insurance policy can be of two types: 

1. Cashless claim 
2. Reimbursement claim 

Cashless claim: In this type of claim, the insured member takes the treatment only at a network hospital of the Third Party Administrator (TPA) or the insurer who is servicing your policy. You have to get the treatment on a cashless basis approved from the insurer.  The insurance company approves the claim as per the terms and conditions of the policy. 
Reimbursement claim:  In this type of claim, the insured member incurs the treatment expenses, in a hospital and pays for the expenses upfront to the hospital/provider. He then files a claim with the TPA or the insurer for a reimbursement. When a claim arises  intimation to the insurance company is required and must be informed within 24 hrs of hospitalisation.  After hospitalisation, you have to ensure that you obtain and keep ready documents such as claim form, discharge summary, prescriptions and bills that you should submit for a claim.