  Measurements of jet production are sensitive to the strong coupling constant,
high order perturbative calculations and parton distribution functions. In this
talk we present the most recent ATLAS measurements in this area at a
centre-of-mass energy of $\sqrt{s}$ = 13 TeV. We present measurements of
variables probing the properties of the multijet energy flow and of the Lund
Plane using charged particles. We will also present new measurements sensitive
to the strong coupling constant. For jet fragmentation, we present a
measurement of the fragmentation properties of $b$-quark initiated jets,
studied using charged B mesons. This analysis provides key measurements with
which to better understand the fragmentation functions of heavy quarks. All
results are corrected for detector effects and compared to several Monte Carlo
predictions with different parton shower and hadronisation models.
