If you just recently started Medicare and was working before, your company sent in the proof of insurance to the IRS. Again, the forms are for your records and don't need to be sent in by you.
This is from the Medicare website (I think you can see it without being signed in there.)
https://www.medicare.gov/forms-help-...rs-form-1095-b
Qualifying Health Coverage Notice & IRS Form 1095-B
What is it?
The Qualifying Health Coverage (QHC) notice lets you know that your Medicare Part A (Hospital Insurance)coverage is considered to be qualifying health coverage under the Affordable Care Act.
If you have Part A, you can ask Medicare to send you an IRS Form 1095-B. In general, you don't need this form to file your federal taxes.
Note
Part A coverage (including coverage through a Medicare Advantage plan) is considered qualifying health coverage. Want to learn more about Form 1095-B and qualifying health coverage? Get official information from the IRS.
Who sends it?
Medicare. Call 1-800-MEDICARE (1-800-633-4227) to ask for a copy of your IRS Form 1095-B. TTY users can call 1-877-486-2048.
What should I do if I get this notice?
Keep your Form 1095-B with your other important tax information, like your W-2 form and other tax records.
You don’t need to:
Take any immediate action.
Send this form to the IRS when you file your taxes.
Send this form back to Medicare.
If you had health coverage other than Medicare during the past tax year:
Your other health coverage provider may send you a separate Form 1095-B.
Contact the health care provider if you have questions about the coverage they provided.
If you need a replacement IRS Form 1095-B, call 1-800-MEDICARE.