The first day of open enrollment for health insurance coverage is fast approaching. Here's everything you need to know about Obamacare and your health insurance policy before you sign up.

What is the healthcare marketplace? The marketplace is where you'll go to sign up for coverage if you're not already insured by your employer, Medicaid, Medicare or the Children's Health Insurance Program. You can shop the marketplace for plans that best fit your needs and get help from websites, call centers and in-person services. The marketplace differs from state to state. The marketplace finder will locate the one in your state.

What is the individual mandate? Also known as the shared responsibility fee, the individual mandate is a penalty you'll be required to pay if you don't have the minimum amount of health insurance necessary. For 2016, the fee was either 2.5 percent of household income or $695 per adult, whichever was higher. The penalty goes up each year to adjust for inflation. You can estimate how much the fee will cost you here.

What is a premium? The amount of money you pay out of pocket each month for insurance each month is your premium. It doesn't include other costs like deductibles and copays. Once you enroll in a plan, your first premium has to be paid directly to the health insurance company.

What is a deductible? Your deductible refers to the amount of money you have to pay before your insurance takes over. 

What is the tax credit? The tax credit is a set amount of money given by the government used to lower your premium and is awarded based on the income estimates and household information you provide on your application. You can decide how much of your tax credit to put toward your premium payments and depending on how much you use, you'll either owe or receive money in your tax return.

What if your existing plan isn't offered this year? If the health care marketplace isn't offering your plan or a very similar plan for the upcoming year, you'll be matched with an alternate plan that fits your needs.

What if your premium went up or you don't like your plan? By logging into your account, you'll be able to check out all the plans that are available to you for 2017. New prices and plans may be available that differ from last years. If you don't choose one of the plans by Dec. 15, you'll be automatically enrolled in a plan chosen for you so you'll be covered come Jan. 1. 

What important dates should I know? There are several dates to pay attention to. We've listed them below.

Open enrollment: Nov. 1 is the first day to enroll, re-enroll, or change your 2017 health care plan. You have until Dec. 15 to sign up if you want your coverage to kick in by Jan. 1

Coverage starts: If you enroll by Dec. 15, your coverage will begin Jan. 1, 2017.

Last day to enroll: Jan. 31, 2017 is the last day to change or enroll in a plan. After this date, you  can only alter your coverage if you qualify for a special enrollment plan.