The IChart interface provides functionality to draw indicators and different types of drawings on charts. There are 31 types of drawings located in the IChart.Type enumeration which can be created, modified and removed by using the IChart interface. Before plotting an object on a chart, one should make sure that the chart is opened. Consider opening a chart for EUR/USD:

IChart chart = context.getChart(Instrument.EURUSD);
if (chart == null) {
    //chart is not opened, we can't plot an object
} else {
    // use chart object to create and manipulate drawings  
}