What would be the best way to get rid of moss off ash fault roofing ti

See if this is what you are looking for . . .

https://www.thisoldhouse.com/ask-toh/getting-algae-and-moss-roof

https://www.washingtonpost.com/lifestyle/home/how-to-remove-moss-from-an-asphalt-roof/2016/01/19/5200fc0a-b497-11e5-9388-466021d971de_story.html?utm_term=.1f6d2c801c74

Good old bleach comes to the rescue. There is enough grooving in asphalt shingles to hold some water, so moss can easily grow in the shadier areas. Cleaning from the top of the roof down with bleach water will kill the moss that is there now, but the spores are blowing onto the roof from somewhere. If you have limbs overhanging the roof, cut them back. You will have to clean the roof more than once a year until the moss stops growing back. Also make sure that there is flashing around every exhaust pipe, chimney, lightning rod and anything else that touches your roof. Best wishes ☺️

Use wet and forget

Can you climb on the roof to wet with a bleach solution or a commercial moss remover? You cannot scrub asphalt shingles.

I used a copper powder on my roof and it works long term...either apply as a powder or mix with water and spray it on. Do it on a calm day when not expecting rain...you don't want it going on your lawn or plantings. You can find it in a lawn and garden store.

Get Lily Miller Moss out either in the shaker bottle or the liquid hose attachment and spray it on the roof, it will kill it. Everyone in Oregon puts it on their roof every spring and fall.