Health services are mostly free at the point of need in the UK. UK residents pay taxes that fund the National Health Service (NHS).
As an international student you'll be able to access NHS services if your course is longer than 6 months. To access NHS services you'll need to pay your Immigration Health Surcharge. You'll pay this as part of your visa application when you arrive and you will need to pay it again for each year you are studying here.
If your course of study in the UK is less than 6 months then you'll need to consider private health insurance.
Learn more about the Immigration Health Surcharge on the government website.