I hope you are implementing code for android, so to make notification clickable you just need to add the pendingIntent with destination Activity name so that you will get the clickable action. Use the below code for reference.
try {
Uri notification = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
Ringtone r = RingtoneManager.getRingtone(getApplicationContext(), notification);
r.play();
} catch (Exception e) {
e.printStackTrace();
}
Intent mainIntent = new Intent(this, TabHostScreen.class);
mainIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
PendingIntent mainPIntent = PendingIntent.getActivity(this, 0, mainIntent, PendingIntent.FLAG_ONE_SHOT);
NotificationCompat.Builder builder = new NotificationCompat.Builder(this, CHANNEL_ID);
builder.setSmallIcon(getNotificationIcon(builder));
builder.setPriority(NotificationCompat.PRIORITY_DEFAULT);
builder.setAutoCancel(true);
//start intent on notification tap (MainActivity)
builder.setContentIntent(mainPIntent);
//custom style
builder.setStyle(new NotificationCompat.DecoratedCustomViewStyle());
builder.setCustomContentView(remoteCollapsedViews);
//builder.setCustomBigContentView(remoteExpandedViews);
long[] pattern = {500, 500, 500};
builder.setVibrate(pattern);
Random rand = new Random();
NOTIFICATION_ID = rand.nextInt(1000);
//notification manager
NotificationManagerCompat notificationManagerCompat = NotificationManagerCompat.from(this);
notificationManagerCompat.notify(NOTIFICATION_ID, builder.build());