This thesis considers recent advances in applications of perturbative Quantum Chromodynamics (pQCD) to hadron collider physics, especially the LHC. In the main part it focuses on combining fixed-order predictions with all-order methods such as resummation and parton showers. After a general introduction to the realm of pQCD we consider a take on the resummation technique in momentum space to provide results for colour singlet production processes for distributions of transverse inclusive observables that vanish away from the Sudakov region. We work at (next-to-)3-leading-logarithmic (N3LL) accuracy and match our results to the (next-to-)2-leading order (NNLO) calculations. We present results for distributions of the transverse momentum of the Higgs boson as well as the transverse momentum of the Z boson and phi-star in the Drell-Yan production process. In the second part we discuss matching of the NNLO accurate calculations to parton showers using the MiNLO technique. The results are obtained by reweighting a sample of hard events at the partonic level with a K-factor that is fully differential in the Born phase space of the considered process. We treat the case of associated Higgs production (VH). We provide validation of our results and a short phenomenological study. In case of the HZ production we have considered the Higgs boson decay into a pair of b-quarks at the next-to-leading (NLO) order in QCD. Similarly we provide a phenomenological overview. In the last part we examine a constraint on the Higgs boson self-coupling that may be obtained in the HL-LHC programme. We work in the framework of Standard Model Effective Field Theory (SM EFT) and consider loop-induced effects of one additional dimension-six operator that modifies the SM Higgs sector.</p
