Hi Shubham,
on my side, those methods work just find:
var noteTakerFeeder = new sap.suite.ui.commons.NoteTakerFeeder({
id: "NTF",
title: "Title of a note"
});
console.log(noteTakerFeeder.getTitle());Unfortunately I can't tell you if it is supposed to be used only together with the NoteTaker. If you check here https://sapui5.netweaver.ondemand.com/sdk/#test-resources/sap/suite/ui/commons/demokit/NoteTaker.html the NoteTaker looks much more convenient 
Regards, Frank