How to get the excat visualization used in Discover page in my custom plugin

@Jagadeesh_ctm

are you referring to the bar-chart on top? if so, that visualization can be created with Kibana-Visualize.

You can look into using the VisualizeLoader to embed the visualization. For details, see https://www.elastic.co/guide/en/kibana/master/development-embedding-visualizations.html. This is an internal feature so YMMV.