Within a Protoplanetary disk (PPD), planets form from micron sized particles, but what are the processes taken for planet formation? How does the evolution of micron sized particles via settlement and coagulation lead to the gigantic planets as the ones in our Solar System? This thesis explores the planet formation process of pebble accretion which is a planet accretion model involving the accretion of smaller bodies onto larger planetesimals. The evolution of micron sized particles into millimetre – centimetre sized pebbles are discussed. These particles will experience growth via settlement and coagulation, radial drift before acting as reservoir for planet cores to accrete and grow from. From the results, it is found that planet formation via pebble accretion is more efficient in the outer regions of the Solar System, where pebble formation was favoured and resulted in smaller inner planets and larger ice giants.