TAN: Line wrapping

A fellow conlanger has asked me either to set my email to produce
a hard carriage return after the seventieth column or to put in hard
carriage returns as I am doing now.  I am working in Netscape
Communicator, and I don't know how to adjust it to shorten
the lines.  When I try to put in hard carriage returns, they don't
show up on my mailer.  Are others of you seeing long lines and
short lines when I don't put in hard carriage returns, and words
crammedtogether like that where I have put in a carriage return
and it doesn't acknowledge it?  This is frustrating.  Could someone
please help this technically phobic user how to tell the computer
that I want shorter lines?  Anyone out there do Netscape mailer?
No time or inclination to download Eudora Pro just yet.

Thanks a million,
Sally Caves