By the Kryder Cares data team · Reviewed by Kris Kryder, licensed agent · Last updated
Both. You sign up for Part A and Part B through Social Security, not Medicare, and a licensed agent like Kris can sit with you while you apply. Once your Part A and Part B are in place, Kris enrolls you in a Medicare Advantage, Medicare Supplement or Part D plan. If you already get Social Security benefits before 65, you are usually signed up for Part A and Part B automatically.
This applies to people turning 65 and people leaving job coverage after 65. The application itself is yours to sign, but you do not have to do it alone.
How it works: who handles each step
Medicare has several parts, and different organizations handle each one:
| Step | Who handles it | When |
|---|---|---|
| Part A and Part B | Social Security (online, by phone or at a local office); automatic if you already get benefits | Initial Enrollment Period: 7 months around the month you turn 65 |
| Medicare Advantage (Part C) or Part D plan | The private plan, through a licensed agent such as Kris or the plan | Your Initial Enrollment Period, then October 15 to December 7 each year (plus January 1 to March 31 for Medicare Advantage members, and Special Enrollment Periods) |
| Medicare Supplement (Medigap) | The insurance company, through a licensed agent | Medigap Open Enrollment: the 6 months after Part B starts at 65 or older, with no health questions |
| Extra Help with drug costs | Social Security (automatic with full Medicaid, SSI or a Medicare Savings Program) | Any time |
Source: Social Security: Sign up for Medicare; CMS: How do I sign up for Medicare?; CMS: Joining a plan. Read October 30, 2026.
What it changes: timing matters more than who calls
Sign up late and you can pay a Part B late enrollment penalty of 10% for each full 12 months you could have had Part B but didn't, for as long as you have Part B (there are exceptions to this, such as job coverage). Part D has its own penalty.
If you or your spouse are still working with employer coverage, you may be able to delay Part B without a penalty, then sign up during an 8-month Special Enrollment Period after the job or the coverage ends, whichever comes first. That is one of the first things Kris checks with you. If you worked for a railroad, you sign up through the Railroad Retirement Board instead.
Kris’s own caution, from her Medicare FAQ: “Many people sign up for Medicare Advantage Plans thinking they are Medicare Supplement Insurance Plans, they are not.” Knowing which one you are joining is the point of sitting down together.
What to do next
About three months before your 65th birthday month, book a time with Kris. Bring your Social Security login or the letter you received, any employer coverage details, your doctors and your prescriptions. She walks through the Social Security application with you, then compares the plans she represents. You can also try the enrollment window calculator.
Sources
- Social Security: Sign up for Medicare
- CMS: How do I sign up for Medicare?
- CMS: Joining a plan
- CMS: Avoid late enrollment penalties
We do not offer every plan available in your area. Currently we represent 14 organizations which offer 119 products in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options. This is a proprietary website and is not associated, endorsed or authorized by the Social Security Administration, the Department of Health and Human Services or the Center for Medicare and Medicaid Services. This site contains decision-support content and information about Medicare, services related to Medicare and services for people with Medicare. If you would like to find more information about the Medicare program please visit the Official U.S. Government Site for People with Medicare located at www.medicare.gov.
This answer is general education, not a recommendation for any specific plan. Figures were current as of October 30, 2026.