  The minimal $U(1)_X$ extension of the Standard Model (SM) is a well-motivated
new physics scenario, where the anomaly cancellation requirement dictates the
new neutral gauge boson ($Z^\prime$) couplings with the SM fermions in terms of
two scalar charges ($x_H$ and $x_\Phi$). In this paper, we investigate the SM
charged fermion pair production mechanism for different values of these scalar
charges in the $U(1)_X$ scenario at future electron-positron colliders, i.e.
$e^+e^-\to f\bar{f}$. Apart from the standard photon and $Z$ boson exchange for
this process, this model features a $t$-channel (or both $s$ and $t$-channel
for $f=e^-$) $Z^\prime$-boson exchange, which interferes with the SM processes.
Considering the dilepton and dijet signatures from the heavy resonance we
estimate the bounds on the U$(1)_X$ coupling $(g^\prime)$ and the $Z^\prime$
mass $(M_{Z^\prime})$. Considering the LEP-II results and prospective
International Linear Collider bounds on the effective scale for the four
fermion interaction we estimate the reach on $M_{Z^\prime}/g^\prime$ for
different center of mass energies. We study the angular distributions,
forward-backward $(\mathcal{A}_{\rm{FB}})$, left-right
$(\mathcal{A}_{\rm{LR}})$ and left-right forward-backward
$(\mathcal{A}_{\rm{LR, FB}})$ asymmetries of the $f\bar{f}$ final states which
can show substantial deviations from the SM results, even for a multi-TeV $Z'$.
This provides a powerful complementary way to probe the heavy $Z'$ parameter
space beyond the direct reach of the LHC, as well as an effective way to
determine the $U(1)_X$ charges.
