  Understanding solar coronal magnetic fields is crucial to address the
long-standing mysteries of the solar corona and solar wind. Although routine
photospheric magnetic fields (MFs) are available for decades, coronal MFs are
rarely reported. Visible Emission Line Coronagraph (VELC) on board Aditya-L1
mission (planned to launch in the near future) can directly measure the MFs in
the inner solar corona. This can be achieved with the help of
spectropolarimetric observations of the forbidden coronal emission line
centered at 1074.7 nm over a field of view 1.05 R$_{\odot}$ - 1.5 R$_{\odot}$.
In this article, we summarize various direct and indirect techniques used to
estimate the MFs at different wavelength regimes. Further, we summarize the
expected accuracies that are required to estimate MFs using VELC's
spectropolarimetry channel.
