How do you find the period and graph the function y=4tanx?

The period of the function $y = \tan x$ is $\pi$, it can be seen from the graph:
The fundamental branche is in $\left(- \frac{\pi}{2} , \frac{\pi}{2}\right)$.
The $4$ doesn't change the period, but only the shape, more steep, as it is possible to see: