does the sun have any magnetic field? if yes, then how?

Sun also has magnetic field.

On the Sun, the magnetic fields connect opposite polarities just as on the Earth. However, while the Earth only has one north and one south pole, on the Sun we observe bits of north and south polarity scattered all over the surface. Furthermore, their position and strengths are constantly changing. The magnetic fields connecting these poles loop out into the corona in a bewildering array of shapes and sizes. They are visible in X-rays because of the hot gas that they trap.