1. Click in the Chart to highlight it / ChartTools becomes visible on the
right hand side of the Title Bar / click in the Format contextual tab (just
beneath ChartTools) / in the Current Selection group select Plot Area in the
only drop down list in that group / now click on the Format Selection buttton
(still in the Current Selection group) / Format Chart Area pop up window
should launch with Fill highlighted on orange on the left hand side / choose
the colour that you want from the Color: drop down arrow / Close.
Your Plot Area will now be coloured as you wish.
2. With ChartTools still in place on the right hand side of the Title Bar /
click on the Layout tab / Analysis group / Lines / High-Low Lines can be
toggled on or off here.
If you want to shade the region defined by the high and low, use area
chart type series. The first should plot the low value, the second
should plot the (high minus low). Format the low series so it has no
fill, and the (high minus low) series so it has the fill color you want.