You can have both employer insurance and Medicare. You may need to sign up with Social Security to get Medicare if you’re not already receiving Social Security benefits. Your human resources department or plan provider can advise you whether to just get Part A or whether to get Parts A and B.
In general, if your employer has fewer than 20 employees, you should sign up for both parts when you turn 65. If your employer has 20 or more employees, you may be able to delay getting Parts A and B. The best course of action depends on your individual situation and your employer, so don’t hesitate to ask what your employer recommends.