According to a law by Dubai Health Authority (DHA) which came into effect in January 2014, it is mandatory or all employers to provide Health Insurance to their employees.
The hospitals and clinics that fall under your policy are based on the cover you opt for.
Mentioning pre-existing conditions is important to ensure they will be covered and that you do not risk coverage for your pre-existing condition being disqualified or your insurance later being cancelled altogether.
There is a maximum claim amount that you can claim in case of an event after which you will have to pay from your own pocket.
It is important to pay the deductible which is your contribution towards the health insurance, after which the remaining amount will be paid by the insurance company.