Q:

Increasing y-axis on plot as it appears it naturally truncates part of the plot

Changing the x-axis is fine and it will allow me to do so. When I want to change the y-axis (2D vertical), an error occurs. It appears as if the mathematica plot is missing some of the graph data.
Is there a way in which I can increase the limits to which the y-axis run?
Like you add {x, -Pi, Pi} to determine the interval of the x-axis, I have tried similar with replacing x with y or x with the function definition.
Code Example: Plot[{Sign[x] - f6[x]}, {x, -Pi, Pi}, {y, -0.5, 0.5}]

A:

I believe you're looking for the PlotRange option to the Plot command.
If you end up with a plot that appears truncated on the vertical axis, for example: 
Plot[E^x Sin[x], {x, -Pi, 3 Pi}]

which produces the following plot:

However, if you use the PlotRange command, as follows:
Plot[E^x Sin[x], {x, -Pi, 3 Pi}, PlotRange -> 10^4]

you will generate the following Plot:

