Accessing Healthcare in the UK
You can pay for NHS healthcare as part of your visa application, this allows you access to the NHS in the UK which is arguably the best healthcare system in the world. It is paid fro through the taxation system.
Emergency or temporary healthcare is available and free at the point of contact whether you are registered or not but it is advisable to register as soon as possible.
Once you are in the UK and have found a location where you are going to settle down you should find a GP & register, this is free but you will need proof of ID and a permanent ( 6 month contract) address.
There are many private healthcare providers, and insurances which you can arrange and pay for on a case by case basis (often called self funded) or through insurance which is also available. This is usually not necessary except in certain cases where people feel a benefit to jumping the waiting list, though Covid may have changed this.
For dentistry, the situation is slightly different. We would advise that you seek out a private dentist and do not rely on the NHS - this is a personal view but we understand that the NHS dentistry is sometimes more of a safety net for the worst case scenarios, than a coverall for your oral health. By all means register with an NHS dentist, but there are many things that they cannot do and for most things other than a general check up & clean you will be sent to a private specialist which, as long as the issue is caught in time, is frequently not too expensive.