Transfer of residential property via nomination

Your father was a joint owner in the property hence hi share in the property shall devolve on all his legal heitrs including your mother.

Your mother can transfer her share including her own share by gift deed in favor of all the three children after which all the three can become joint owners of the property.

Then you can mutate the revenue records to your names after which you can transfer the share certificate to your names in the housing society 

How can we mutate the revenue records what all documents required since my father expired without the will do we need take the succession or LOA or as a nominee in society records we can transfer the property on our name  via gift deed of my mother

First obtain a legal heirship certificate indicating the legal heirs of yo0ur deceased father after which you can transfer the revenue records of the entire property to all your names. After this your mother can execute a registered release deed relinquishing her rights in the  joint family property.

After that the property will devolve jointly on you and your siblings alone. 

In case of practical doubts you can take the assistance of an experienced lawyer in the local and proceed as advised

Why is that the siblings require the mother to relinquish or gift her rights and title  in the jointly held property?

My Mother is 86 years old now and we don't want any further hassles of transferring the property post her demise and also currently all the 3 siblings are in healthy relationship hence we want the same to be transferred smoothly in our name without any hassles of transfer

What hassles? After her lifetime, the property would devolve upon all the siblings.

By the way, who is in possession/occupation of the property? Who is taking care of the mother?

Can the application for the legal heir certificate done online and in how much time it is provided.

Currently the residential property is on rent and the rent has been deposited into the bank account jointly owned by my mom and sister.  My mom is staying with me and i am taking care of her.  As mentioned we all siblings enjoy healthy relationship.  Mom is old and immobile we just wanted to divide  all the money & property  pertaining to parents smoothly dont want the hassle of getting will probated etc to get the property  transferred  post her demise. Now also we need to get the legal heir certificate as mentioned above for our father share to be transferred on her and on our name post his demise.  This is the reason we need to get this process completed in her presence.

Instead of repeatedly approaching this forum with same question or similar query, you can contact an advocate in the local and proceed as suggested which will be a better option instead of getting stranded for unable to take any decision reading too many opinions by various experts of different legal forums