Are a line and a point not on the line sometimes or always coplanar?

A line and a point not on the line
are always coplanar.
This follows from the fact that to define a plane we need three distinct
points.

Or putting it in another way, it is always possible
to draw a plane through any three points. Though if we have four points one of them may
not lie on the plane that is drawn using the other three
points.

To define a line we only need two distinct points.
In your problem, we have two points that lie on the given line and another point not
lying on the line. These three points always define a unique
plane.

Therefore, a line and a point not
lying on the line are always coplanar.