H1B from H4 in USA

I have a question regarding H1B application for a H4 holder staying in USA.

  1. How soon can a H4 holder apply for a new H1B lottery ?
  2. I have an approved petetion of H1B which had a expiry on 2017 November. My employer has applied for a cap exempt. In case the petetion is rejected , can I apply for a fresh H1B through in cap from USA after finding a employer ?
  3. In case my new H1B gets picked and approved 2023 , am I eligible to work from 2023 October ?

USCIS opens registration every year in March.



I meant to ask , is there a duration of stay with H4 that enables me to apply for a fresh H1B ?
When should I reach US in H4 to apply for the H1B lottery in 2023 March ?

There is no such concept of duration. You can travel with H4 visa on H4 status and once in the US cam apply for change of status to H1B is yiu had H1B approved in past. If no past H1B then find a sponsoring employer and apply in lottery in March.