diff --git a/pipeline/outputs/elasticsearch.md b/pipeline/outputs/elasticsearch.md
index 1bcb59529..c18f6b720 100644
--- a/pipeline/outputs/elasticsearch.md
+++ b/pipeline/outputs/elasticsearch.md
@@ -15,6 +15,7 @@ operational Elasticsearch service running in your environment.
 | `Host` | IP address or hostname of the target Elasticsearch instance | `127.0.0.1` |
 | `Port` | TCP port of the target Elasticsearch instance | `9200` |
 | `Path` | Elasticsearch accepts new data on HTTP query path `/_bulk`. You can also serve Elasticsearch behind a reverse proxy on a sub-path. Define the path by adding a path prefix in the indexing HTTP POST URI. | Empty string |
+| `header` | Add additional arbitrary HTTP header key/value pair. Multiple headers can be set. | _none_ |
 | `compress` | Set payload compression mechanism. Option available is `gzip`. | _none_ |
 | `Buffer_Size` | Specify the buffer size used to read the response from the Elasticsearch HTTP service. Use for debugging purposes where required to read full responses. Response size grows depending of the number of records inserted. To use an unlimited amount of memory, set this value to `False`. Otherwise set the value according to the [Unit Size](../../administration/configuring-fluent-bit/unit-sizes.md). | `512KB` |
 | `Pipeline` | Define which pipeline the database should use. For performance reasons, it's strongly suggested to do parsing and filtering on Fluent Bit side, and avoid pipelines. | _none_ |