do companies issue Appointment letter in USA

[chnrbk]

Hi,

I have joined a indian based IT company in USA on FT basis,a publicly traded company in USA. They have sent me a offer letter but not issued me the appointment letter. I just wanted to know if this is usual process in USA or every employer must issue the appointment letter?
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[AKV1006]

Hi I want some information about Job change on H1B visa. Here is my scenario:

1) I got my Visa from May 2012 to Dec 2012 for Employer A. When i entered in US the I94 expiration date was again the same Dec 2012
2) Before expiring the Visa my employer filed the extension of the visa...