Measurement of jet substructure observables and jet fragmentation properties using the ATLAS detector

Jet substructure observables and properties of jet fragmentation are sensitive to a wide range of Quantum Chromodynamics (QCD) phenomena. They are essential to probe a new regime of QCD at hadron colliders. Measurements of jet substructure observables are also crucial to improve our understanding of the jet substructure properties used in many searches for physics beyond the Standard Model (BSM). These proceedings present some measurements of jet substructure and jet fragmentation observables performed with 33~fb$^{-1}$ of proton-proton ($pp$) collision data collected by the ATLAS experiment at the Large Hadron Collider (LHC) at centre-of-mass energy of $\sqrt{s} = 13$~TeV. The measurements are corrected for detector effects, represented as particle-level distributions and are compared with state-of-the-art Monte Carlo (MC) simulations and theoretical calculations.