diff --git a/help/waterfox.md b/help/waterfox.md
index a21a8c95..62c44d52 100644
--- a/help/waterfox.md
+++ b/help/waterfox.md
@@ -5,3 +5,9 @@
 - Take a screenshot of the entire page          `screenshot --fullpage`
 - Take a screenshot of the visible window only  `screenshot`
 - Restart the browser                           `restart`
+
+## Preferences
+
+Waterfox has 2 preference files: `prefs.js` and `user.js`.
+
+`prefs.js` are the settings defined by the browser and `user.js` is an optional file that you can create. `user.js` takes precedence over `prefs.js` and will replace the settings in `prefs.js` when Waterfox is started.