There are many evidences, but I will identify three here.
First, God left his fingerprints in nature. This was discussed under intelligent design and irreducible complexity. Specified information systems like the DNA molecule, order and predictable laws in nature are only possible as a result of intelligence and not chance. So the evidence in nature points to the existence of an intelligent being, but doesn’t reveal his identity or name (see Romans 1:18-20).
Second, God left His fingerprints in history. Study of the evidence for Jesus Christ as recorded in the eyewitness New Testament accounts will lead to the reasonable conclusion that He is indeed the incarnation of God to earth (the true significance of the Christmas celebration). The evidence for the reliability of the New Testament records of Jesus and His deity are detailed in chapters two and three of my book, Surprised by Faith. So the evidence of history reveals the name of the Designer (see John 1:1-18 and 1 John 1:1-3).
Third, God continues to leave His fingerprints on the lives of those who embrace Jesus as their Savior. People of every walk of life (teachers, laborers, lawyers, doctors), every social status (peasants, middle class, governors), every geographical region (U.S., Russia, China, Africa), every age (children, youth, adults): all share a common testimony that their faith in following Jesus has changed their life in very positive ways. Such uniform testimony supports the contention that God exists (see 2 Corinthians 3:18; Colossians 3:1-17).