You can file for health insurance claim in two ways-
In cashless claim, you will have to undertake medical treatment at a hospital in the network of the insurer. The insurer will directly settle your medical bills with the hospital and you will have to pay only the deductible or amount which is excess.
In reimbursement claim you usually undertake medical treatment at a hospital which does not fall under the network of the insurer. You will have to pay your medical bills out of your pocket and file for a claim later on.