What an immigrant need to find a good job?
Which formarions the employers are seeking?
the immigrant must have experience?
I think it’d be pretty much the same as what anyone else needs except obviously their papers and a good command of the language that they will need.
In Britain there are well-known and accepted formal qualifications which show an employer your level of English. For instance:
http://www.cambridgeesol.org has:
General English exams
FCE (First Certificate in English)
CAE (Certificate in Advanced English)
CPE (Certificate of Proficiency in English)
Certificates in ESOL Skills for Life
Professional English exams
BEC (Business English Certificates)
BULATS (Business Language Testing Service)
Cambridge ILEC (International Legal English Certificate)
Cambridge ICFE (International Certificate in Financial English)
ESOL for Work (UK only)
These qualifications appear to have wide recognition globally:
http://www.cambridgeesol.org/recognition/index.html
Maybe there is a better qualification specifically for USA though.