How and from where to get legal heir or succession certifica

The question which is asked is as below:

The House which was in my father's name and now that he is no more how can it be transferred in my mother's name. The house is located in India in Gujarat State - Ahmedabad city under Auda area. Right now me, my younger sister, my younger minor brother (14 year old) and my widowed mom stay in the same house.

My father passed away 2 years ago. He took housing loan and was paying monthly installment and when he passed away, loan payment was pending, so we paid remaining loan amount from his PF amount and settled all the account so now we dont have any debt. The finance company which granted us loan returned all the papers of house on the full payment of loan.

Now my question here is how do we transfer the house in my mother's name. We receive light bill still in father's name so what can we do so that it comes in mother's name?

FYI - My father didn't left any WILL so I think by default the house will belong to my mother but what legal procedure we have to follow to get the house transfer in her name.

Please give me advice. I posted my question here so that I can get good advice as to what legal procedure we have to follow to transfer the house in my mother's name.

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To this I was told that in absence of will my mom and we 3 siblings become legal heirs of equal share, and we need to apply for succession certificate. One of my neighbour told we need to get legal heir certificate for all members of house. But how to get that, from where to apply, what necessary documents we need to get those certificates. My family is of opinion that we all four members (my mom and us 3 siblings) should become joint owner of this house. So in that case how to transfer ownership in our name and in what name light-bill phone-bill should come. How to apply for change in name of light-bill or phone-bill. Pls help and advice.