[DOCS] Add reference for ingest pipelines in Enterprise Search (#91357) (#91376)

(cherry picked from commit cd6be58)

Author: leemthompo

docs/reference/ingest.asciidoc

@@ -446,6 +446,14 @@ If you run {agent} standalone, you can apply pipelines using an
 you can specify the `pipeline` policy setting in your `elastic-agent.yml`
 configuration. See {fleet-guide}/install-standalone-elastic-agent.html[Install standalone {agent}s].
 
+[discrete]
+[[pipelines-in-enterprise-search]]
+=== Pipelines in Enterprise Search
+
+When you create Elasticsearch indices for {enterprise-search-ref}/index.html[Enterprise Search^] use cases, for example, using the {enterprise-search-ref}/crawler.html[web crawler^] or {enterprise-search-ref}/connectors.html[connectors^], these indices are automatically set up with specific ingest pipelines. 
+These processors help optimize your content for search.
+Refer to the {enterprise-search-ref}/ingest-pipelines.html[Enterprise Search documentation^] for more information.
+
 [discrete]
 [[access-source-fields]]
 === Access source fields in a processor