  Production of quarks and gluons in hadron collisions tests Quantum
Chromodynamics (QCD) over a wide range of energy. Models of QCD are implemented
in event generators to simulate hadron collisions and evolution of quarks and
gluons into jets of hadrons. PYTHIA8 uses the parton shower model for
simulating particle collisions and is optimized using experimental
observations. Recent measurements of event shape variables and jet
cross-sections in pp collisions at $\sqrt{s}$ = 13 TeV at the Large Hadron
Collider have been used to optimize the parton shower model as used in PYTHIA8.
