Guaranteed Issue Rights
Guaranteed issue rights are situations in which insurance companies must sell you a Medigap policy, must cover your pre-existing conditions, and cannot charge you more because of your health. These rights usually apply in specific circumstances, such as losing certain other coverage. The situations that trigger them are set by federal and state rules.
This is general education, not personalized advice, and plan details change every year. For all of your options, contact Medicare.gov, 1-800-MEDICARE, or your local State Health Insurance Assistance Program (SHIP) at shiphelp.org.