A good source of information for questions like this is Ethnologue. This site has a huge database on language, and according to Ethnologue's figures Hebrew today has 5.3 million speakers in total. Most of these are in Israel where Modern Hebrew, along with Arabic, is the official language.
Modern Hebrew was largely developed in the 19th century. At this time Ancient or classical Hebrew was rarely used except in literature and religious ritual, but it began to be revived and when the State of Israel was founded in 1948 Hebrew, which was already in official use there, became an official state language.
Modern Hebrew is influenced by other languages to an unusual extent. This is mainly because most of its speakers are either not native speakers or have at least one other language, so the outside influences are strong. There is an Academy in Israel, rather like the Academie Francaise, which decides which new words and forms are acceptable.