Medicare Enrollment

How Do You Actually Sign Up for Medicare?

By Tai Thao, Licensed Independent Medicare Agent, Golden Milestone Services · Updated October 27, 2026

Ready to enroll in Medicare but unsure which website to use or what to do first? The main step is to sign up for Medicare Part A and Part B through Social Security, unless you are being enrolled automatically. Medicare.gov explains the rules, but Social Security handles most applications for these two parts. Your exact steps depend on whether you already receive Social Security benefits, have Part A, or are leaving coverage from a current job.

Do you need to apply for Medicare, or will it start automatically?

First, find out whether you must submit an application at all. People already receiving Social Security retirement benefits at least four months before turning 65 are generally enrolled automatically in Part A and Part B. They should receive a Medicare welcome package and card before coverage begins. Some people receiving qualifying disability benefits also enroll automatically under different rules.

If you are not yet receiving Social Security retirement benefits, do not assume Medicare will start just because you turn 65. You may need to apply. The Medicare.gov sign-up questionnaire helps identify which path fits your situation. If a card arrives, check the effective dates for both parts rather than assuming they are identical.

Where do you go to sign up for Medicare Part A and Part B?

Use the Social Security Medicare sign-up page to begin an application. It explains how to apply for both Part A and Part B, Part A alone when appropriate, or Part B if you already have Part A. You can apply for Medicare without starting Social Security retirement benefits at the same time. This distinction matters if you plan to keep working or delay retirement payments.

For a first-time application, follow Social Security’s online instructions and use your secure account when prompted. If you cannot use the online route, contact Social Security for assistance. People who worked for a railroad may have a different enrollment contact through the Railroad Retirement Board. Avoid entering sensitive information into an unfamiliar website that merely claims to process Medicare applications.

What information should you have ready before applying?

Gather basic identification details before opening the application. Social Security says applicants should be prepared to provide their Social Security number and place of birth. It also asks about health insurance, including the dates when job-based group coverage started and ended, particularly coverage held after age 65. If you are adding Part B to existing Part A, have your Medicare number and a usable email address available.

Check the dates against your employer or benefits records rather than guessing. If you have a spouse whose current employment provides your insurance, keep that information handy too. You may be asked for additional documents depending on your circumstances. Review the application carefully before submitting, and retain any confirmation or instructions you receive for your records.

When should you submit your Medicare application?

For most people first eligible at 65, the Initial Enrollment Period runs from three months before the birthday month through three months afterward. Applying in the earlier part of that window generally gives you more time to confirm the effective date. The start date can depend on which month you apply, so check the official enrollment guidance rather than choosing a date based only on your birthday.

Do not confuse the process of applying for Part A and Part B with the annual October-to-December period for changing certain Medicare coverage choices. The annual period is not a general opportunity to sign up for Part B for the first time. If your first eligibility window has passed, determine whether a Special Enrollment Period applies before assuming you must wait.

How do you add Part B if you already have Part A?

If your Medicare card lists Part A but not Part B, you do not need to repeat the same first-time application without checking the correct process. Social Security offers a separate way to request Part B. The Medicare.gov ready-to-sign-up page directs people to the appropriate application or form based on why they are adding Part B.

Someone adding Part B after current-employment group coverage ends may need employer verification using form CMS-L564. Someone using the General Enrollment Period may instead be directed to form CMS-40B. These are different situations; using the wrong route can slow down the process. Read the current instructions for your situation and submit supporting paperwork as directed by Social Security.

What if you are still working and covered by an employer plan?

Do not assume everyone with employer insurance should make the same Medicare decision at 65. If you or your spouse has group health coverage based on current employment, you may qualify to delay Part B and later use a Special Enrollment Period. Ask the employer’s benefits administrator whether the group plan is expected to pay before or after Medicare and whether you need Part A or Part B while still employed.

When qualifying current employment or its group coverage ends, an eight-month Part B Special Enrollment Period may apply. COBRA or retiree coverage does not, by itself, extend that eight-month clock. If you want to avoid a coverage gap, coordinate your Medicare application with the end of job-based insurance instead of waiting until the final day. The working-past-65 guide explains the main exceptions.

What should you check if you have a Health Savings Account?

People contributing to a Health Savings Account need an extra review before applying. Medicare Part A can sometimes begin retroactively when you enroll after age 65, and HSA contributions for months covered by Medicare can create tax consequences. Social Security and Medicare warn people to coordinate HSA contributions with Medicare enrollment and retirement-benefit applications.

What happens after you submit the application?

Watch for communications from Social Security and follow any request for missing information. After enrollment, you should receive a welcome package and Medicare card showing your Medicare number and coverage start dates. Check that both Part A and Part B appear if you intended to enroll in both. Keep the card information secure and use the effective dates when coordinating any other coverage.

Once you have your Medicare number, you can set up a secure account at Medicare.gov and review how to receive your Medicare benefits. Original Medicare includes Part A and Part B; Medicare Advantage is another Medicare option for receiving those benefits. Prescription drug coverage and supplemental coverage are separate decisions with their own rules. Enrolling in Part A and Part B does not automatically complete every coverage decision.

What if you missed your chance to sign up?

Start by checking whether you qualify for a Special Enrollment Period, including one tied to qualifying employer coverage or certain exceptional circumstances. If no special window applies, the General Enrollment Period for Part B runs January 1 through March 31 each year, with coverage generally beginning the month after enrollment. Waiting may create a gap and may lead to a late enrollment penalty, depending on your circumstances.

Use the official sign-up timing tool before deciding which form to submit. If you are uncertain, ask Social Security to confirm the correct enrollment category. An adviser can help explain the sequence, but the government enrollment decision and application are handled through the appropriate federal agency.

What is the simplest Medicare sign-up checklist?

1. Check whether you are being enrolled automatically.
2. Confirm the correct enrollment window for your situation.
3. Ask your employer about current-job coverage if you are still working.
4. Gather your identification, insurance dates, and any required employer forms.
5. Apply through Social Security or follow the applicable official instructions.
6. Review your confirmation, Medicare card, and Part A and Part B start dates.
7. Only then review how you want to receive Medicare coverage and whether you need additional coverage.

For Wisconsin residents, the application process for Part A and Part B is federal; the same Social Security starting point applies. The useful local step is to organize your employer and retirement coverage details before applying. If you would like help understanding the sequence and the questions to ask, use the Medicare appointment page. You remain in control of when and how you submit your government application.