Two point charges $+q$ and $+q$ are placed at a distance $r$ from each other. The electrostatic force between them is:

According to Coulomb's law, \[ F = \frac{1}{4\pi\varepsilon_0} \frac{|q_1q_2|}{r^2} \] Since $q_1=q_2=q$, \[ \boxed{ F = \frac{1}{4\pi\varepsilon_0}\frac{q^2}{r^2} } \] The force is repulsive because both charges are positive.