diff --git a/Documents.md b/Documents.md
index 834d5ed..2392ce9 100644
--- a/Documents.md
+++ b/Documents.md
@@ -1,4 +1,9 @@
 ======= ngrok =======
 - login to https://dashboard.ngrok.com/
-- copy token line to login on your OS
+- copy the token line to log in on your OS
 
+======= change npm version =======
+```bash
+nvm install v21
+nvm use v21
+```