To open the Data Window, double-tap anywhere on your desired chart until a Crosshair appears. Once the Crosshair is active, a small box icon will appear in the top left corner of your selected chart. Tap that icon to bring up the Data Window!
By default, the Data Window will display the High, Low, Open, and Close of the candle currently covered by the Crosshair. Below that, it will show the values for any indicators you currently have loaded on your chart.
To hide the Data Window, tap the X icon within the Data Window Modal. To remove the Crosshair and Data Window completely, simply double-tap anywhere on the chart again!