  In this paper we study the accretion of matter onto the black holes and the
shadow images obtained by an infalling accretion flow of gas in a theory of
massive gravity (MG) with a spontaneously breaking Lorentz symmetry. This black
hole solution is characterized by mass $M$, scalar charge $S$ and the parameter
$\lambda$. In order to extract the astrophysical results of our analyses,
firstly, we have assumed a specific range for the parameter $\lambda$ to
constrain the scalar charge $S$ using the EHT result. To this end, we have
studied the effect of the scalar charge on the intensity of the electromagnetic
radiation from the black hole. Moreover, we investigate the behavior of
polytropic as well as the isothermal fluid flow onto massive gravity black hole
and notice that accretion starts from supersonic/subsonic flow, passes through
the critical point using particular model parameter and ends near the horizon.
We also analyzed the mass accretion rate in the presence of various fluids
which indicates important signatures. We also elaborate on the possibility to
analyze the phase transition and the stability of the black hole using the
shadow formalism.
