Acquiring a Medicare Beneficiary Identifier or MBI card involves interacting directly with official federal healthcare administration systems. If you are turning sixty-five or qualify for Medicare due to specific disabilities, the Centers for Medicare & Medicaid Services automatically mails your official Medicare card containing your unique MBI number to your address on file with the Social Security Administration. If your card is lost, stolen, or damaged, you can securely retrieve your official MBI number or request a replacement card by logging into your official online Medicare account or contacting support.