Production measurements of heavy-flavour hadrons in pp collisions provide a stringent test to pQCD calculations.
Analysing their production as a function of charged-particle multiplicity allows us to study multi-parton interactions, which are expected to have a relevant role in charged particle production at high energy at the LHC. Moreover, the comparison with theoretical models allows investigating the contribution of colour reconnection in hadronization mechanisms of heavy quarks into hadrons.
In this report, the production measurements in pp collisions at $\sqrt{s}$ = 13 TeV of D mesons (D$^0$, D$^+$, D*$^+$) as well as their dependence on multiplicity are presented. The results are compared with similar studies for other particle species, with D-meson measurements performed at $\sqrt{s}$ = 7 TeV, and with predictions from Monte Carlo event generators.