Pine automatically appends ~/.signature (if it exists) to your messages.  
To change Pine's signature features in Pine 3.89 (and earlier versions) you 
need to edit your ~/.pinerc file directly.

Type...                 In order to...
=======                 ==============
cd                      Change to your home directory (i.e., $HOME or ~)
pico .pinerc            Use the pico editor to edit your .pinerc file.
^w                      Search for . . .
feature-list            . . . ``feature-list''


Edit your .pinerc so that it contains this line:

feature-list=signature-at-bottom

If you want more than one feature in your feature-list then they need to
be comma separated like this:

feature-list=old-growth,
	signature-at-bottom


If you want to use a file other than ~/.signature for your signature
edit the following line:

signature-file=