Divorce in case of Desertion

Hello Sir, I got married in Oct'12 and we stayed together for hardly 3 months ..Since Feb'13 until now, we have been living separately.So, I have decided to mutually seekl legal divorce after 6 long years .Earlier ,in 2014 end, she sent an agreement on a notarized stamp paper with her sign and claimed that the agreement paper will suffice the purpose of divorce. But I was told that written agreements wont serve the purpose. In order to take legal divorce, we need address and contact detaild.For the past few years, we do not have a clue of what her address and location is. We don't have a clue of her mobile number .In case of her absconding ,how do I proceed. I want to not cause inconvenience to her by taking help of police or other sources. Please advice of the best possible ways of taking divorce. I know her address where she lived during the year 2013. But after 2014, there is no clue. Please note: We did not register our marriage.However my office documents bear her name ( as dependent)