Simplify the following text for a Grade 3 native English-speaking person.
Original: Jehovah 's Witnesses emphasize use of God 's biblical name , represented in the original texts by the Tetragrammaton , and in English they prefer to use the name , Jehovah . They believe that Jehovah is the only true God , the creator of all things , and give him the title `` Universal Sovereign '' .
Simplified: They believe that God 's name is Jehovah .