How do I know whether Obamacare applies to me?If your employer provides health insurance for you, you likely won’t have to do anything Tuesday, when enrollment begins. The president has said you can keep your doctor and your plan.For others — those without insurance — it’s more complicated. The law requires virtually all U.S. citizens and legal residents to have coverage or pay a penalty. In Texas, which has opted not to expand Medicaid, people without insurance will have to buy it, either through the Health Insurance Marketplace (the exchange) or an insurance broker. Financial help will be available for those who qualify, based on income. When do I have to decide whether to buy health insurance, and what happens if I don’t?Beginning in 2014, virtually all Americans must have health insurance or pay an annual penalty to the government. For an individual, the fine in 2014 is $95 or 1 percent of income, whichever is greater, rising to $695 or 2.5 percent of income by 2016. The fine for uninsured children in 2014 is $47.50 per child, capped at $285 per family. Those fees also climb each year.Federal researchers predict that about 6 million people could be fined by 2016. Those who owe penalties would see their tax refunds docked. What are health insurance exchanges and how do they work?Exchanges are the online markets where individuals and small businesses can buy private health insurance. Think of them as one-stop-shopping destinations similar to Amazon.com that are supposed to give consumers a quick way to compare insurance policies. Consumers are expected to be able to see all their options in the exchanges and choose their health plans based on price, benefits and other features. Many participants will qualify for tax credits to help ease the cost. The subsidy is based on income and is available to individuals making up to $45,960 or a family of four making up to $94,200. Enrollment begins Tuesday, and coverage starts Jan. 1. How will coverage and services differ under Obamacare?Policies sold on the exchanges are more comprehensive than what is typically available to individuals in the current market, which is dominated by bare-bones plans. It will resemble what a successful small business offers its employees. All plans in the exchange, and most outside it, must cover Essential Health Benefits, including hospitalization, doctor visits, prescriptions, emergency room treatment, and maternal and newborn care. Most must cover certain preventive services. Those include routine vaccinations, vision and hearing tests for children, and screenings for diabetes, high cholesterol, colon cancer and high blood pressure.Insurers can’t turn away people or charge more because of health problems or chronic illnesses. Premiums are the same for men and women. Older adults can’t be charged more than three times what young people pay, but insurers can charge smokers up to 50 percent more. Will I be forced to change doctors or health plans even if I don’t want to? And will my choices for both be limited?Probably not. You can maintain your providers if you have job-based insurance and can choose any available primary-care provider in your insurance network. However, the influx of patients who will be newly insured under the Affordable Care Act could overwhelm the healthcare system in some areas. You might see a physician assistant or nurse practitioner rather than a physician. If I buy my own insurance, can I keep it or do I have to change?If you have individual insurance — a plan you bought yourself rather than what you get through an employer — you can keep it or change to a new plan if you choose. I keep hearing about bronze, silver, gold and platinum. What do those terms mean?They refer to the escalating levels of benefits (and premiums) of policies sold on the exchanges. The lowest-cost bronze plan is designed to cover 60 percent of medical expenses, with the individual paying 40 percent. The highest-cost platinum tier covers 90 percent of expenses.