Usage patterns
〈人〉が国民健康保険に加入するfor someone to enroll in national health insurance
Since I became self-employed, I enrolled in national health insurance.
国民健康保険料を納めるto pay national health insurance premiums
I have to pay my national health insurance premiums every month.
国民健康保険証を提示するto present one's national health insurance card
I showed my national health insurance card at the hospital.