  Dark matter particles from the Galactic halo can be gravitationally trapped
in the solar core or in external orbits. The enhanced density of dark matter
particles either in the solar core or in external orbits can result in the
annihilation of these particles producing gamma rays via long-lived
intermediate states or directly outside the Sun, respectively. These processes
would yield characteristic features in the energy spectrum of the subsequent
gamma rays, i.e., a box-like or line-like shaped feature, respectively. We have
performed a dedicated analysis using a 10-years sample of gamma-ray events from
the Sun collected by the Fermi Large Area Telescope searching for spectral
features in the energy spectrum as a signature of dark matter annihilation. In
the scenario of gamma-ray production via long-lived mediators we have also
evaluated the dark matter-nucleon spin-dependent and spin-independent
scattering cross section constraints from the flux limits in a dark matter mass
range from 3 GeV/c$^2$ up to about 1.8 TeV/c$^2$. In the mass range up to about
150 GeV/c$^2$ the limits are in the range $10^{-46} - 10^{-45}$ cm$^{2}$ for
the spin-dependent scattering and in the range $10^{-48} - 10^{-47}$ cm$^{2}$
for the spin-independent case. The range of variation depends on the decay
length of the mediator.
