Position and motion in the Solar System:
A simple answer is that the Sun is situated at the centre of the Solar System. But, the sun is affected by the gravitational pull of all the planets ever so slightly. The rocky inner planets don’t ado much. Jupiter, Saturn, Uranus and Neptune have a significant impact on the motion of the Sun. The most dominant gravitational affect on the Sun is from Jupiter, the king of the planets. Jupiter’s gravity forces the Sun to revolve around a common revolution point called the Barycentre.
The Barycentre is the centre of mass of Jupiter and Sun and is located outside the Sun. The Sun is always within 1-2 million kilometers of the Barycentre.
Position and Motion in the Galaxy:
The sun is located in the Milky Way Galaxy. It is situated in the Orion arm of the Milky Way, approximately 27000 light years from the Galactic centre. The sun is orbiting around the milky at a very high speed, approximately 220 km/second or 800.000 km/h (490,000 mi/h). At this speed, it travels one light year (9.46 trillion kilometres) in 1400 years and 1 AU (150 million kilometres) in 8 days. Even at this high speed, the Sun takes approximately 240 million years to finish one orbit around the milky way.
Position and motion in the Universe:
The suns motion relative to the CMB (Cosmic Microwave Background) is the same as the Milky Way. They move at a velocity of 630 km/s relative to the Cosmic Background. As far as position is in the Universe is concerned we are located in the Local group of galaxies which is located in the Virgo Supercluster which is in turn located in the Laniakea Supercluster.