  We present an analysis of the theoretical and observed light curve parameters
of the fundamental mode (FU) classical Cepheids in the Magellanic Clouds in
$V$- and $I$- photometric bands. The state-of-the-art 1D non-linear radial
stellar pulsation (RSP) code in MESA (\textsc{mesa-rsp}) has been utilized to
generate the theoretical light curves using four sets of convection parameters.
Theoretical light curves with two chemical compositions: $Z=0.008$ and
$Z=0.004$ appropriate for the Large Magellanic Cloud (LMC) and Small Magellanic
Cloud (SMC), respectively, covered a wide range of periods ($3<P (\rm{d})<32$).
The observed light curves are taken from the OGLE-IV database. We compare
theoretical and observed Fourier parameters (FPs), and investigate the
period-luminosity (PL), period-colour (PC), and amplitude-colour (AC) relations
as a function of pulsation phase for short ($\log{P}<1$), long ($\log{P}>1$)
and all periods. The multiphase relations obtained from theoretical and
observed light curves in the PL/PC/AC plane are found to be dynamic in nature,
with the effect more pronounced at $\Phi \sim 0.75-0.85$. Furthermore, a
contrasting behaviour of the theoretical/observed multiphase PL and PC
relations between the short and long periods has been found for both LMC and
SMC. The analysis shows that multiphase PL relations are more stringent to test
the models with observations over the FPs. Distances to the LMC/SMC determined
using long period Cepheids are found to be in good agreement with the
literature values when the term $R_{21}$ is added to the PL relation.
