There are several methods of adding a label to a plot. You can use
PlotLabel,
Labeled, or interactively add text to a plot using . For a description of adding text to plots using , see
How to: Add Text outside the Plot Area and
How to: Add Text to a Graphic.
To add a centered label to the top of a plot, use the
PlotLabel option:
You can control the appearance of the label by wrapping it in
Style options:
If the plot has a background color, the plot extends to include the label:
To put a label underneath a plot, like a caption, use
Labeled:
To use the same font and style that is used in graphics, set the label style to

:
In this case, the background of the plot does not include the label: