The number of water molecules present in the coordination sphere of ${\mathrm{FeCl}}_3,6{\mathrm{H}}_2\mathrm{O}$ is

FeCl₃​⋅6H₂​O is actually [Fe(H_2​O)₄​Cl₂​]Cl⋅2H₂​O.
Out of three chlorine atoms, two are present in the coordination sphere and one is present in the ionization sphere.
Out of six water atoms, four are present in the coordination sphere and two are present in the ionization sphere.

$\left[\mathrm{Fe}{\left({\mathrm{H}}_2\mathrm{O}\right)}_4{\mathrm{Cl}}_2\right]\mathrm{Cl}\cdot 2{\mathrm{H}}_2\mathrm{O}$