I have t wo CISCO ROUTER at different location How can connect them for Telephony

Your question has way too many answers. It depends on what country you are in... what type of communications services you have... T1, E1, ISDN, etc.

What model router is it? Is it a vendor provided router or is it owned by you? Is it an Internet router? Do you have VPN in mind? Based on the fact there your question is such a broad one and there are so many possibilities, you would be best suited to contacting a consultant in your area.