Not sure, but it looks like cedar clapboard.
Other wood species are also common.
It is installed similar to shingles on a roof.
Big box stores might carry it, or they certainly can order it.
There are many different widths, and thicknesses, and profiles, some are flat, some are thinner at the top edge, some have beveled edges, etc.
You can take off some of that metal corner trim to get a good view of how individual boards look.
Take measurements of width, thickness, shape, etc, and lots of pictures.
BTW, that bottom board resting on the ground might be rotted all around the house.
And is likely full of carpenter ants or termites or both.
You can replace those with solid pvc trim boards, which are paintable.
Or treated wood, but that will still suck up water, pvc will not.