Intent class function putExtra(String name, char[] value) is able to add extended data to the intent. The first parameter (name) must include a package prefix. For example if we wanted to create a new email activity and pass the value some email address we would do the following (assume we call from activity class):
Intent email = new Intent(getActivity(), EmailActivity.class);
email.putExtra(MainActivity.CURRENT_EMAIL, "someemail@domain.com");
where as MainActivity.CURRENT_EMAIL acts as a key in this case. Its value must contain package name, for example: "com.example.EMAIL". Further reading in documentation under section Extras: https://developer.android.com/guide/components/intents-filters.html