second phone number for an existing line

[DCPhil]

Have an established line at my home with three jacks/phone for this phone number.  Called Verizon and was told that it is possible that one can prepare the existing line to accommodate a second phone number.  Apparently, the second phone number can be established from the district office if prepared properly.  If not, there is a $100 charge.  Looking for the best advice on how to do this.  Is there a jack that can replace one existing jack to allow a second phone numer to ring?  I am aware that there are two-line phones

Have searched the internet and surprisingly this specific arrangement is not well covered.  Seeking an informed response and hopefully links to a how-to with images.

[Hubrisnxs]

Step by step adding a nd line

looks like a really good walk through with pictures and examples.

And here is a great E-How article

Telephone Wiring Diagram for Standard Telephone Jacks for the Home