Think of current like water pressure and distance like standing away from a running hose: the stronger the water current (or electrical current), the stronger the splash, and the further away you stand, the weaker the felt effect.

B is directly proportional to I, and inversely to r (BIR: B equals I over r).

According to the Biot-Savart Law or Ampere's Circuital Law, the magnetic field ($B$) at a perpendicular distance ($r$) from an infinitely long straight wire carrying current ($I$) is given by the relation $B = \frac{\mu_0 I}{2\pi r}$. This shows that $B$ increases proportionally when the current $I$ increases, and decreases inversely as the distance $r$ from the wire increases.

Always remember that field strength is directly proportional to current ($B \propto I$) and inversely proportional to distance ($B \propto \frac{1}{r}$) for straight conductors.