  We have studied the timing and spectral properties of the BeXB 4U 1901+03
during the 2019 outburst using \textit{NuSTAR}, \textit{Swift}, and
\textit{NICER} observations. Flares are in all observations and were of tens to
hundreds of seconds duration. Pulse profiles were changing significantly with
time and the luminosity of the source. An increase in the height of the peak of
the pulse profiles was observed with energy. The pulse fraction increases with
energy and at the end of the outburst. The variation of the pulse profile with
time indicates the transition of the pulsar in different accretion regimes. The
absorption like feature at 10 keV shows a positive correlation with the
luminosity and along with other spectral parameters this feature was also pulse
phase dependent. As the distance to the source is not precisely known hence we
cannot confirm this feature to be CSRF and also cannot ignore other possible
explanations of the feature. Another absorption like feature about 30 keV was
observed in the spectra of the last two \textit{NuSTAR} observations and has
line energy of about 30.37$\pm$0.55 and 30.23$\pm$0.62 keV respectively. We
have also studied the variation of the line energy, width, and optical depth of
this feature with pulse phase. The softening of the spectrum along with the
increase in pulse fraction at the end of the outburst and absence of pulsation
after 58665.09 MJD suggest that pulsar has entered propeller phase, also abrupt
decrease in \textit{Swift}-XRT flux supports the fact.
