Yes, $\psi_x : E' \to \Bbb{R}$ defined by $\psi_x(f) = f(x)$ is an element of $E''$.
That even give us a canonical injection from $E$ to $E''$ ( $x\mapsto \psi_x$)
But note that often not all elements of $E''$ can be written as such (there's not always a bijection between $E$ and $E''$)