When you go to the doctor’s office, the doctor will bill the insurance company for your services. Once the bill has been processed, you will receive an Explanation of Benefits Payment statement, or EOB. Your EOB will show any charges you may owe out of pocket. Your doctor will send you a bill for the exact amount you owe. You can use money from your HSA to pay that bill. Your doctor may require you to pay at the time of service if your deductible is not met.