How can we find transfer function of this n/w
Replace the capacitor C with an impedance of value \$Z_c = 1/(Cs)\$ and apply voltage division rule. 

ie, 
$$ E_0(s) = E_1(s) \times \frac{Z_c}{R+Z_c}$$

or, 
$$\frac{E_0(s)}{E_1(s)} = \frac{Z_c}{Z_c+R}$$