diff --git a/lib/ansible/utils/module_docs_fragments/opennebula.py b/lib/ansible/utils/module_docs_fragments/opennebula.py
index 6b6e7c03149..233d036a78a 100644
--- a/lib/ansible/utils/module_docs_fragments/opennebula.py
+++ b/lib/ansible/utils/module_docs_fragments/opennebula.py
@@ -21,6 +21,7 @@ options:
     api_password:
         description:
             - The password or token for XMLRPC authentication.
+              If not specified then the value of the ONE_PASSWORD environment variable, if any, is used.
         aliases:
             - api_token
     validate_certs: