The Diversity Visa Lottery is a program of the U.S. Government. It started over 20 years ago. For each Visa Lottery 50,000 Diversity Green Cards are made available. The visas are given to people born in countries with low immigration rates into the US. A low rate means that less than 50,000 people immigrated from a country over the previous five years.

Why is the current Visa Lottery called DV-2018 ?
Because the visas are officially issued in 2018. 

If I win do I get a Green Card right-away ?
No. You win a chance to apply for a Green Card. You must submit a Visa Application and successfully complete the Visa Procedure that follows. After you arrive in the U.S. the Green card is issued.

If I win can I bring my spouse and my children ?
Yes. Your spouse can also submit a Visa Application.
You can bring a child/children if they are unmarried and still under 21 years of age when the visa is issued.