The study of the multiplicity dependence of heavy-flavour hadron production in pp collisions provides insight into heavy quark production mechanisms and into the interplay between hard and soft processes in particle production. Further, multiple parton interactions may also play a significative role in the heavy-flavour production at LHC energies. In this proceeding, we present the measurement of the heavy-flavour hadron decay electron yield as a function of transverse momentum and charged particle multiplicity at mid-rapidity ($|\eta| <$ 0.8) in pp collisions at $\sqrt{s} =$ 13 TeV. Electron identification is done within 0.5 $<p_{\rm T}<$ 4.5 GeV/$c$ with the Time Projection Chamber (TPC) and the Time-of-Flight (TOF) detectors of the ALICE apparatus. The measurement of electrons from heavy-flavour hadron decay is expressed in terms of the ratio of the yield in a particular multiplicity interval to the multiplicity integrated yield (self-normalized yield). The result is given as a function of the relative charged particle pseudorapidity density within $|\eta| <$ 1.