  Recent studies of high-multiplicity events in small collision systems
(proton-proton and proton-lead) have drawn research interest towards the
possibility of the formation of partonic medium in such systems. One of the
important consequences of the formation of dense partonic medium is quenching
of high-momentum final-state particles resulting in several experimental
observations such as suppression in nuclear modification factor $R_{\rm AA}$,
modification of jet shape observable $\rho(r)$ and jet fragmentation ($z^{\rm
ch}$) distributions, etc. In this work, we study $\rho(r)$ and $z^{\rm ch}$ for
inclusive charged-particle jets in proton-proton (pp) collisions at
$\sqrt{s}$~=~13~TeV using PYTHIA~8 Monash~2013 Monte Carlo simulation. We show
that the color reconnection (CR) and multiparton interaction (MPI) mechanisms
in PYTHIA~8 can lead to an increased rate of jet production. We also find that
the mechanisms of MPI and CR and change in the gluonic contribution in
high-multiplicity events result in significant modification of $\rho(r)$ and
$z^{\rm ch}$ compared to those in minimum bias events for 10~$<p_{\rm
T,\,jet}^{\rm ch}<$~20~GeV/$c$. We notice a direct connection of $\langle
N_{\rm MPI}\rangle$ and gluonic contribution with the amount of modification in
$\rho(r)$ -- the larger the number of MPIs and/or gluonic contribution, the
larger the amount of modification of $\rho(r)$.
