As Sophia explained the geographical correct name is the Netherlands. If I say that I am from the Netherlands people sometimes don't understand but if I say I am from Holland, people will understand because in many languages they use Holland, Holanda, Olanda, etc. In fact Dutchmen also use Holland in sport events. At the World Cup in Brazil also the Dutch fans will yell "Holland". Some Dutchmen living in the east and south will get offended because Holland is more related to the west of the country.

I'm not tutor of English. You have 3rd options: 1st Netherlands, 2nd Holland and 3rd Low Countries In my opinion is more correct you say Netherlands... In Portuguese we say: Holanda and Países Baixos, and the more correct is Holanda... So I choose Netherland, is allways how I write/talk

Technically speaking by saying 'Holland' you refer to only two of twelve Dutch provinces (North-Holland, and South-Holland). So, the correct name for the entire country would be the Netherlands. However, the name Holland's become somewhat synonymous with the Netherlands when referring to the country in English. In Dutch I rarely ever hear anyone say they're from Holland, instead we say we're from 'Nederland'.

"The Netherlands" (= Nederland) is the whole country while "Holland" only refers to the two provinces "Noord Holland" and "Zuid Holland" in the Western part of the country.