What is the ruling on subscribing to health insurance provided by the oil company through foreign companies, given the user's ignorance of the terms of the contract between the two companies?

If the insurance provided by the employer for employees is commercial insurance based on gharar (uncertainty) and gambling, which is mostly the case, then it is not permissible to participate in it voluntarily. However, if the worker has no choice in it, then there is no sin upon him. But if it is cooperative takaful insurance, then there is no harm in it, and the worker may benefit from it.