If a conducting wire is placed along the x-axis and a current flow through it in the positive direction, it creates a magnetic field around it. The direction of the magnetic field at a point (0,-2) is negative z-axis i.e. inside the plane.
In the positive x direction
Direct your thumb towards the direction of current in the straight wire. The curl of the fingers gives the direction of the magnetic field. If you point your thumb in the positive x-direction and place your fingers at y-axis, the fingers direct towards negative z-direction. Hence, the direction of the magnetic field is along the negative z-direction.