Medicare-X Choice Act of 20 21 This bill establishes and funds the Medicare Exchange health plan, which allows individuals who are not otherwise eligible for Medicare to enroll in a government-administered health insurance plan. The Centers for Medicare & Medicaid Services (CMS) must offer such plan in certain individual health insurance exchanges beginning plan year 2022 and offer it in all individual health insurance exchanges beginning plan year 2025. CMS must offer the plan in the small group market in all geographic areas for plan year 2025. The plan must cover primary care services without cost sharing and meet the same requirements, including essential health benefits, as existing health insurance exchange plans. Unless they opt out, health care providers enrolled under Medicare or under a state Medicaid plan must participate in the plan and are reimbursed at Medicare rates. The bill establishes a grants program for community organizations, educational institutions, and health agencies to create service partnerships and establish interactive data systems for health care providers. Additionally, the bill expands the premium tax credit available for plans purchased through an exchange and eliminates the restriction on the Department of Health and Human Services negotiating prescription drug prices for Medicare.