can h2 b file on approved H1 B petition

USA H1B Visa
1

  1. Is it mandatory to apply LCA through icert portal for fresh H1 B as portal is still not working?

  2. Through iCert portal,employer can file H1 B or H2 B on approved H1 B petition?

  3. Can H2 B change to H1 B with new employer like H1 B transfer happens?