Before filing a claim, get the doctor to first provide you the itemized bill, which mentions all of the services you have received as well as their cost. Get the health insurance claim form from the insurance company and fill it with complete honesty. The insurance company will have listed down the instructions to be followed while filling up the form, including where you need to send it.
It is a always a good idea to make a copy of the filled-up claim form as well as of all the receipts in case they get lost or misplaced. Now, submit the form and the original receipts to the insurance company's third party administrator. If the documents are found to be valid, your claim application will be processed and the benefits (sum insured) will be paid out to you.