Annotations

Use the tools provided on the Plot Editor ribbon in the Annotation group, to add Text, Callout Text and Text Box objects, dimension lines and arrows to the plot.

Click Edit labels to put the plot into Edit Labels mode and enable the tools in the Annotation group.
Click the Snap to Point button to toggle Snap to Point mode on and off. When Snap mode is turned on, the mouse cursor will snap to the nearest point.
To set Labelling options, click the Edit Annotation Sets button.
  The Active Options combo box on the Annotation toolbar indicates the current working set. Selecting [Defaults] will reset everything to reasonable system defaults.
 
Use the Format Picker tool to pick up (arrowhead, colour, line width, angle units etc.) format settings from an existing annotation object.
Use the Format Painter tool to apply the current format settings to selected annotation objects.
Click the Horizontal Dimension Line tool to add a horizontal dimension line to the plot that measures the horizontal distance between any two points (along the x-axis).
Click the Vertical Dimension Line tool to add a vertical dimension line to the plot that measures the vertical distance between any two points (along the y-axis).
Click the General Dimension Line tool to add a dimension line to the plot that measures the length of diagonal line segments.
Click the Measure Angle tool to add an Angle measurement to the plot.
Click the Arrow tool to add an Arrow line to the plot.
Click the Text tool to add a Text label to the plot.
Click the Text Callout tool to add a Text Callout label to the plot.
Click the Text Box tool to add a Text Box label to the plot.
Click the Edit Text button to edit the selected Text or Callout Text label.

Annotation Frame

Plot Annotations

Plot Labels