So Our nikah held almost 6 years ago.only nikah.we were not in any husband wife relationship. after which i got admission in mbbs and he didn't continued his studies after FA.i didn't wanted to marry him amd thus convinced him to divorce me. I convinced my family.he said it will be difficult to say the words if we colud prepare stamp paper.so we did and he signed it.although emotional but knowing what was written in it and with his consent.4 years have passed.i am married to another man now and he is also married to some other woman.now he started texting me and my husband that we were comitting zinnah as he never divirced me.he wants revenge from me and wants to go to court against us saying that those signatures are fake and he never divorced me.so i just wanted to confirm if only the signature is enough for divorce because according to some people i know it is compulsory to say the words.
Words are a standard way to divorce and not obligatory in each and every case. For example, if you happen to dislike your husband and wanted a divorce but he wont say the words then you can forcefully get a divorce by initiating "Faskh".
However if he does consent then you may file for Khul or Khul'a. Both Khul and Faskh are the names goven to the legal processes where a wife initiates the divorce. The main dofferences are that in Khul a husband agreement to divorce is present while in Faskh its not. Further reading could be done here
The main reasons for initiating faskh should be such as cruelty (darar) or impotence (if undisclosed to bride at time of marriage) or if a husband cannot provide his wife with basic marital obligations, such as shelter or maintenance.
A woman must have clear evidence in her favour to be granted khulʿ
Therefore, Your husband may not want to divorce you but you do have a right to take a forceful divorce from him and since he has willingly signed the document and remained silent for all these years only to wake up now, then he surely is nothing more than a blackmailer. He did have the option to challenge your legal document or could have consulted you back then but the didn't. So, the blame is on him and not you.