One of the primary causes for the occurrence of observed features on the Sun is its magnetic field. The traditional way of measuring the solar magnetic fields is through the Zeeman effect. Over the decades, as the precision of the observing instruments has improved, our understanding of the solar magnetic fields has deepened. We now know that there exist fields on the Sun which remain invisible to the Zeeman effect. This apparent invisibility of the fields can be due to their lower strength, orientation, or their tangled nature. However, these fields can still be detected with the help of the Hanle effect.