diff --git a/llvm/docs/Phabricator.rst b/llvm/docs/Phabricator.rst
--- a/llvm/docs/Phabricator.rst
+++ b/llvm/docs/Phabricator.rst
@@ -47,6 +47,18 @@
   arc diff HEAD~
 
 
+Sometime you may want to create a draft revision to show the proof of concept
+or for experimental purposes, In that case you can use the `--draft` option. It
+will either create a new draft revisoin or convert the original revision to a
+draft revision depending on your local branch status. The good part is: it will not
+send mail to llvm-commit mailing list, patch reviewers, and all other subscribers,
+buildbot will also run on every patch update:
+
+::
+
+  arc diff --draft HEAD~
+
+
 If you later update your commit message, you need to add the `--verbatim`
 option to have `arc` update the description on Phabricator: