How to pay for medicare when Social Security Benefits go away

EDIT In the event I need to change the way I pay for Medicare EDIT Most people pay for medicare through their SS pay. I managaed my late mother's medicare payments by paying for medicare through direct deposit. If this becomes necessary in the future, how do I set this up to pay for medicare via direct deposit;

Edit I edited this to make it clear I have question about changing the way I pay for Medicare EDIT