There is no icon.  Within a tax return go to Tools > Letters.

Maybe my model of ProSeries came with the XLT trim.  I have an icon two notches to the left of the green where do I enter button.

I don't have that.  There is an icon directly to the right of the calculator and to the left of the invoice but I've never used it, hence Tools > Letters. Too many icons up there.  I'm an old DOS drop down menu person.