I'm not Christian myself but I have many Christian friends who have tattoos/body art. Is this something that is forbidden in Christianity?
The Bible mentions tattoos just once, at Leviticus 19:28, which says: “You must not put tattoo marking upon yourselves.” This prohibition was for the nation of Israel and should not be taken to apply to the New Covenant relationship that GOD has established with Christians. I am not aware of any major Christian denominations that directly address tattoos nor do they prohibit them. There are some smaller groups, however, that prohibit tattoos. The simple answer is that nothing in the New Covenant prohibits Christians from getting tattoos.
The Bible says:
Do you not know that your bodies are temples of the Holy Spirit, who is in you, whom you have received from God?
Most tattoos are of something the person considers is important (e.g. the name of a girl friend), it is clearly not correct define the “Temple of God” in such a way. This excludes most but not all tattoos.