how do i reduce width of text in received emails to print within 8 1/2" paper
The width of text in received emails is too wide to print within normal margins of 8 1/2 inch paper, so some of the text at the end off each line does not appear when the email is printed.
Opaite Mbohovái (3)
File > Page Setup = check-mark the Shrink to Fit preference
The shrink to fit option does nothing, and the % option stays frozen at 40.
Too wide at a 40% scale??
File > Print Preview
Try changing those settings to 100% and Shrink to Fit in the Print Preview window. You need to print from that Preview window immediately, so the change in settings is "held" by Firefox.
If that doesn't fix your problem, try saving that "text" to a file and then viewing it in a Text program like Notepad or Wordpad that has "wrap" enabled. I would suspect that something with "wrap coding" in that file isn't completely with Firefox's ability to display text files and "wrap" when it needs to "wrap" to keep the text on the "page".