With living standards coming under pressure, a Stocks and Shares ISA's a great way of producing some extra cash. Taking it to the maxThe most than can be invested in a Stocks and Shares ISA each tax year is £20,000. If they invested £4,000 in each of the five highest-yielding FTSE 100 shares, they could unlock annual passive income of £1,260 (at 1 August). And unfortunately, it's difficult to predict the future so a stock's dividend history is often used as a guide. Top of the pileThat's why many income investors have Legal & General (LSE:LGEN), the "leading financial services group" in their portfolios.