You set the following variables for a Exponential Moving Average study:
Smoothing
A technique that assigns exponentially decreasing weights (by the factor you define) to datapoints as the average moves through time to produce a smoothed series rather than sharp, sudden changes in price. For a list of smoothing factors based upon the number of days in the moving average (n), see Smoothing Factors.
Series
Specifies the prices used (Open, Close, High, or Low) to plot the study for the given time period.
Moving Average Color
Indicates the color used to display the study.