Hi Finally did it by editing content.txt file which has got style sheet and json data
Added applyNumberFormat like this
"cellStyleXfs":[{"$":{"count":"1"},"xf":[{"$":{"numFmtId":"5","fontId":"0","fillId":"0","borderId":"0","applyNumberFormat":"1"}}]}]
and
"cellXfs":[{"$":{"count":"2"},"xf":[{"$":{"numFmtId":"5","fontId":"0","fillId":"0","borderId":"0","xfId":"0","applyNumberFormat":"1"}}
also added style sheet element
"numFmts":[{"$":{"count":"1"},"numFmt":[{"$":{"numFmtId":"5","formatCode":"$#.###,00"}}]}],
Which works perfectly after generating workbook this format will be added in as customFormat and new entry is made in the custm number format
Thanks for all the help !!! hurry !!!