How does distance affect magnetic force?

Hint: To find how distance will affect the value of magnetic force, first it is needed to find a relation between magnetic force and distance, then it will become easy to define how distance will affect the magnetic force. Coulomb’s Law can be used here as it shows the relation between magnetic force and distance.
Formula used:
$F=k\dfrac{{{m}_{1}}{{m}_{2}}}{{{r}^{2}}}$

Complete answer:
The equation of magnetic force is like Coulomb’s Law, as Coulomb’s Law also supports the rules of magnetism.
According to Coulomb’s Law, it is an experimental law of physics that quantifies the amount of force between two stationary, electrically charged particles. The electric force between charged bodies at rest is conventionally called electrostatic force or Coulomb force.
The law states that the magnitude of the electrostatic force of attraction or repulsion between two-point charges is directly proportional to the product of the magnitudes of charges and inversely proportional to the square of the distance between them.
$F=k\dfrac{{{m}_{1}}{{m}_{2}}}{{{r}^{2}}}$
where,
$\begin{align}
  & k=\text{Constant} \\
 & {{m}_{1}}\,\And \,{{m}_{2}}=\text{Magnitude of Charge} \\
 & r=\text{Distance} \\
\end{align}$
So, from the above formula it is clear that,
$F\propto \dfrac{1}{{{r}^{2}}}$
Therefore, Magnetic force is inversely proportional to the square of distance between the
two point charges.

Note:
Coulomb’s Law is not only used in calculating electrical force but also used in calculating magnetic force. The formula remains the same in both the cases just the meaning of charge changes in both the cases. In case of electric force, it considers electric charge and in case of magnetic force it considers magnetic charge of the particles. The meaning of constant and distance remains the same in both the cases.