Q. Will Christians be present on the earth at the time the anti-Christ appears? Does the anti-Christ appear before or after the Rapture?
A. It depends on your definition of appearance. Most of us believe he’s alive today, so in that sense he has appeared on Earth. But 2 Thes. 2:7 says that he won’t be allowed to release his secret power of lawlessness until the restrainer is taken out of the way. The Restrainer is widely held to be the Holy Spirit resident in the Church. So his official introduction to the world can’t take place until after the Rapture.
There will no doubt be Christians in the world at that time because the disappearance of the Church will bring many fence sitters to faith.