How to submit CMS-40B and CMS-L564: online, by fax, by mail or in person

Once your forms are filled in, the last step is getting them to Social Security before your window closes. The rules say your request must be signed and filed with Social Security during your enrollment period (42 CFR 407.22). Here are your options.

First: do you have Part A?

CMS-40B and Social Security's "Part B only" path are for people who already have Part A. If you don't, you apply for Medicare instead. Social Security lets people 65 and older apply online for Parts A and B at ssa.gov/medicare/sign-up, or you can call. Social Security's manual says people who aren't eligible for premium-free Part A use form CMS-4040 to enroll in Part B only (POMS HI 00805.075). Either way, CMS-L564 is still your proof of job-based coverage.

Your four options at a glance

Option 1: Apply online

Social Security's Sign up for Part B only page says you can apply online when you're ending an employer group health plan, any time of year during the Special Enrollment Period.

• Have these ready: your existing Medicare number and a valid email address (Social Security lists both for the Part B only path).
• You can't save and come back. Social Security's manual says the online application can't be saved and revisited (POMS HI 00805.277). Gather your dates, employer details and scanned proof first.
• You sign with an eSignature to submit.
• Upload your proof. Social Security's Medicare booklet says to upload your evidence of group health plan coverage, such as the signed CMS-L564 (SSA Publication 05-10043).
• It's only for the job-based Special Enrollment Period. The online service doesn't cover the exceptional-conditions periods or international volunteers.

Medicare.gov describes the steps a little differently: apply online, have the employer fill out CMS-L564, and send the completed L564 to your local office by fax or mail. If you can't upload it, that's your fallback.

Check your Part B Special Enrollment Period in 2 minutes. Start the free Part B check →

Option 2: Fax

Fax your signed CMS-40B and the CMS-L564 (or other proof) to your local Social Security office. Social Security's manual says the office address and fax number are in the office locator at SSA.gov/locator. Keep the fax confirmation page.

Option 3: Mail

Mail the same papers to your local office's address from the locator. Both forms say to send them to your local Social Security office. A mailing service with tracking gives you proof of when you sent it and when it arrived.

Option 4: In person

CMS says you can also submit CMS-40B by visiting your local Social Security office. The L564 lists in-person help there too. Bring a copy of everything for yourself.

Help by phone

Social Security's number is 1-800-772-1213 (TTY 1-800-325-0778). It's available Monday through Friday, 8 a.m. to 7 p.m., in most U.S. time zones. For Spanish, press 2. You can call for help with the forms or to make an appointment. Free counseling is also available from your State Health Insurance Assistance Program at shiphelp.org.

What to keep

• A copy of your signed CMS-40B.
• A copy of the CMS-L564 with both sections filled in.
• Copies of any other proof you sent, such as W-2s or pay stubs.
• Your fax confirmation, tracking number, or online confirmation.
• A note of the date you sent it, and of any calls: the date and who you spoke with.

After you apply, Social Security's sign-up page has a link to check the status of your application.

Timing

• Medicare.gov suggests signing up about a month before your job coverage ends, so there's no gap.
• If your employer is slow, don't wait. See what to do if your employer won't sign.
• Social Security advises not to cancel any health insurance you have until after your Medicare coverage begins.

Not sure which month to put in the start-date box? See when does Part B start.