I have a line below the WiFi/battery area in my lock screen. What does that mean?

On The iPhone X Control Center is accessed from the top right corner, not from the bottom like on other iPhones. This is because swiping up from the bottom on the iPhone X is used for accessping the home screen.

This is normal. It just indicates that you can access control center from there.

Can you post a picture of it. I do not have it on my 6s. I access the control center by swiping up from the bottom.

It's to show people where to drag down to open the Control Center.

It disappears when you move to any other screen.