For all of the MMC healthcare benefits except for the Vision Discount Program, you must formally enroll to participate. You can enroll for coverage by accessing MMC PeopleLink's MMC Benefits Online, at www.mmcpeoplelink.com. You must enroll within 30 days of the date you become eligible or during Annual Enrollment. You may be able to make changes to your elections during the plan year if you have a qualified family status change.