H4 to H1 Change of status Query

My H1B processing in India got 221g, Documents submitted to USCIS, Passport not taken,In the processing. My Wife in US on H1.
Can i Apply for H4 to Travel US ?
What Happens if H1 is approved while in US ?
Can Change of status from H4 to H1 possible?

I guessing your H1B visa stamping received 221g and now waiting on visa approval?

Yes you can apply for H4 visa.

If you are not present in India while your H1B is processed by the consulate in India, your H1 visa may be denied.

Yes. If this is first time H1B thwn your employer may be able to file H1B amendment before October 1st and request change of status.