When I start using my number card as an insurance card, when I turn 75, do I not have to take any procedures to become an insured person under the medical system for elder senior citizens?

If you are 75 years old, you will be automatically insured by the medical system for elder senior citizens from your 75th birthday, so both those who use your My Number Card or those who do not join You do not need to apply.
If you are a member of the company's health insurance union, you may need to take some steps to withdraw from the employee health insurance. For more information, please check with your health insurance union.