Paper Chromatography is based on the difference in the rates at which the components of a mixture are adsorbed. The material on which different components are adsorbed is called Stationary phase which is generally made up of Alumina, Silica gel or Activated Charcoal.
The mixture to be separated is dissolved in a suitable medium and it is called Moving phase. The moving phase is run on the stationary phase, the different compounds are adsorbed on stationary phase at different rates.