Thank you for your kind reply.
i tried to edit following two labels. first i copy Label.properties and paste and rename with CustomLabels_ar.properties. after that i edit following two labels in CustomLabels_ar.properties and stop the WHD with WHD stop and start it again but still nothing change on client page on request and history button.
lbl.subject = \u0645\u0648\u0636\u0648\u0639
i also change
btn.request = \u0633\u062C\u0644
btn.request = \u0637\u0644\u0628 \u062E\u062F\u0645\u0629
is there any other change i have made to do this successful GUI language.