H1B - Filing

I have very basic question. Post submission of documents to USCIS, rom Attorney every H1B application will get tracking number so that tracking can be done the candidate. What stage the Tracking numbers are issued ? As soon as they receive application or only after application picked-up in lottery? If no luck in lottery there will be no tracking number ? Only Rejection letter is the proof that Application did not picked-up and we need to wait till attorney or employer will notify us the same. Is there any tracking site will help after 7th april onwords to check the status?

Please clarify – H1B Aspirant for this year.

For selected petitions, receipt number is generated and informed.

For non-selected petitions, rejection notices are sent.

There is no other way to track your application beside above 2.