I have the homephone connect from verizon, how do you disconnect the landline wire on a older house so you can connect other phones, I also have internet so I don't want to disconnet the wrong wire so the internet won't work

You need to go out to the phone box and disconnect wires from terminals, may be a red and green or a blue/white, white/blue pair. Provide a photot if you can.
If it has a test jack, unplug and lock the box so ot can be messed with, if someone was to hook backup, you would be backfeeding a dial tone back to the phone company, any shorts on their wiring would affect your phones.
Physical disconnection is preffered,