Nearly two million Americans are now covered by the Affordable Care Act.
But many people are still waiting to see how and if their lives will be changed by President Barack Obama's health care law.
Coverage begins Wednesday for anyone who signed up for health insurance by December 24.
But anyone who does not have a health plan that meets the government's standards of quote "minimum essential coverage" may face an Individual Mandate fee that will be tacked onto their tax return next year.
Low-income individuals may be able to waive the fee.
There is a three-month grace period that allows most Americans to wait until April 1 to sign up.
Businesses with 50 or more employees will also be required to offer health benefits to their employees.
Open enrollment for 20-14 ends on March 31.
The White House hopes to have seven million Americans signed up by the deadline.