Hi @kyaw, welcome to the discussion boards!
keyword property is showing up as a result of Dynamic Mapping. This data was indexed into Elasticsearch without an index mapping pre-defined, so Elasticsearch created one for you, based on the dynamic field mapping rules.
Simple text fields often get index as two separate fields: the original, and
original.keyword, which contains the same data as the original field, but mapped as a
keyword data type in Elasticsearch. Keywords are typically more useful in Kibana visualizations than their corresponding text fields, but don't benefit from stemming or other analysis features of Elasticsearch.
If you don't want this behavior, then you can create your index mapping before you ingest your data, and explicitly tell Elasticsearch what the index should look like.