Piya,
Sure in the main config.json file of your app just add showAttribution false to the mapOptions (line 11):
"mapOptions": {
"extent": {
"xmin": -9588945.63048467,
"ymin": 3961163.9078186783,
"xmax": -9521681.045593806,
"ymax": 4027893.4335115473,
"spatialReference": {
"wkid": 102100
}
},
"showAttribution": false,
"logo": false,