If your employer offers health insurance and/or other kinds of coverage (like dental, vision, disability, etc.), and you decline the opportunity to enroll, you can waive coverage. (The form your employer asks you to sign is called a Waiver of Coverage.)
Your decision to waive coverage can be based on coverage you have elsewhere (such as through a spouse) or because you do not want to pay for the coverage.
If you decline coverage at your initial enrollment, you may still be eligible to enroll later – at your group’s next Open Enrollment period or if you experience a Qualifying Life Event.