How to fill the area on purpose
Rows stay in sequence. The first row is the left edge. Do not sort by value. Each series is one filled line. If the series are parts of a total, turn on stack areas. The top of the stack is the total, and each band is a part, in the same spirit as a stacked bar drawn across time. If the series are alternative measures, leave stacking off. Overlapping areas need colors that stay readable when they mix, which is why the fills are partly transparent.
A smooth curve is optional. It softens a monthly series and it can hide a sharp month. Prefer straight segments when a spike is real. Points mark the months you actually have. Leave them on for a short series so nobody thinks you measured every day. Axis titles carry the unit. Kilowatt hours on the vertical axis prevents the filled shape from being read as money or as people.
Set the vertical minimum and maximum only to match a neighboring figure. An area that does not reach a honest baseline exaggerates the fill. Zero is the natural floor for a volume. If the values are an index that never nears zero, say that in the subtitle so the filled shape is not read as a share of nothing.
The legend names the series. Color the bands so a reader can follow one series across the months. Value labels at every point get noisy on an area. Use them for a short chart, or leave them off and let the axis speak. The grid is a quiet ruler. Turn it off if the fill is already busy.
Export PDF when the figure goes into a document, PNG when it goes onto a screen and the title must stay sharp, and JPEG when you have no choice. If you do not need the fill, the line chart is calmer. If the horizontal axis is not a sequence, do not use an area. The tool grid opens the line chart, the stacked bar, and the table maker. The picture stays on this device until you download it.