"I have got 1099 from etrade and it did not have any sign of 100 shares sold for taxes. How do we report this in tax filing"
I assume that number of shares figure should have been "42".
If the sale of shares "for taxes" was not reported on the 1099-B that you received then you have to reporting obligation. Cash raised from shares sold "for taxes" is passed back to the employer, who pays the government, and includes that amount it the various "withholding" boxes on the W-2.
It seems to vary how shares sold "for taxes" are reported on the 1099-B; in some cases they are and in some cases they aren't.
Tom Young