Jehovah is the name of the God of Israel (God of the Jews)
The name is called the tetragammon and the pronunciation is lost because no one remembers how to say it.
So sometimes you will read of Yahweh, Jaweh, Jehovah. Hebrew does not have vowels like English. The generally accepted rendition is Jehovah. Remember, that the Jewish people hold the name of God to be holy, and where Christians say and write GOD, the Jews will not. They will say and write G_D as a form of respect to the Divine.