[RWebb]

use a spray with iron sulphate etc. in it - should only kill the moss, which is very sensitive to ferrous compounds rel. to vascular plants

that will kill it; not remove it - pressure washer will do that but abrade the shingles somewhat

a strip of Cu along the roof line works great long term ($$$)

maybe trim some trees to get more sun in those areas - moss will grow if the environment favors... moss