How to move the legend to an arbitrary position, e.g. inside the plot?

The legend can be moved inside the plot as shown below.

You can also display the legend above or below the plot. In the figure below the legend is plotted below the plot.

Setting the legend position is done from Plot->Layout->Edit…. Make sure you select the tags as shown in the figure below, starting from the upper Chart, Legend, Position.

Make sure  is checked if you want the legend to be moved inside the plot. But if you want the legend positioned below the plot make sure  is turned off and the  radio button is checked.

Note: If storing the setup, these changes will be kept.