Moss is a primitive plant species that thrives in shady and moist conditions. It can take root in many locations and prefers acidic soil. A prime location for moss to grow is in between paver stones. Paver stones trap moisture underneath and in between them. The spaces in between usually aren't suitable for growth of many plants, but moss can thrive in these poor conditions. Moss can either be controlled chemically or by physically removing it. Usually environmental conditions have to be altered to prevent moss from returning.
Remove the moss by hand. With the small spaces between the pavers, you will have to manually remove all the moss. If the moss is elevated, a putty knife or wire brush may work to scrape it up.
Use chemical products like iron sulfate or ferrous ammonium sulfate if you don't want to manually remove it. A good mixture is 3 ounces of the chemical per 5 gallons of water. This will treat 1,000 square feet, so it should be more than enough. Spray the moss using a pump-up sprayer.
Thin out trees and remove other objects that cause the area to be shaded. Moss thrives in shady and moist locations. By removing the shade, more sun and drier soil will result. The moss will then decline and eventually die out.