If a magnetic needle is kept in a non-uniform magnetic field, it experiences:

Uniform Magnetic Field: Magnetic field is said to be uniform if the magnetic induction has the same magnitude and the same direction at all the points in the region. A uniform magnetic field can be prepared by making a comparatively long cylindrical coil.

Non-uniform Magnetic Field: If the magnetic induction varies in magnitude and direction at different points in a region, the magnetic field is said to be non-uniform. The magnetic field due to a bar magnet is non-uniform.

In a uniform magnetic field, the two poles of the magnetic needle experience equal and opposite forces. Hence, the needle experiences only the torque due to the magnetic field and there is no force.

When an iron needle is placed close to a bar magnet, magnetization takes place. The poles do not experience a uniform magnetic field, the two poles of the magnet experience forces of unequal magnitude although the direction is different for each pole. So, the magnetized needle experiences a force as well as torque.