You have to work an average of 20 hours per week over a 6-month period to stay eligible for insurance & other benefits. If you're a new hire, you need to average 20 hours a week over a 3-month period to become eligible.
Specific health insurance options vary by state but you'll be able to choose from several plans. Some plans will have a relatively low cost on your paycheck but require you to pay more if you need healthcare. Other plans will cost more on your paycheck but will also cover more of your expenses.
From your post history you seem to already be a partner, so the best thing to do is to log into
$1, where you can check your eligibility and see exactly what options will be available to you.