Transfer property to my sister name

Due to sudden death of my mother there is no will made and we are 03 siblings and the property is on my mother name now me and my brother want to transfer on my sister name the house or in future we need to sell the property, property tax is paid by builder we only give monthly maintenance as well no society is still form so please advise we sibling our ready to transfer on my sister name or else will there be problem to sell the flat because my mother last wish to sell the flat and to buy new, please advise what is to be done in this case ration card we dont have my mother Aadhar card pan card is there, i cant afford much want to know the easy way to transfer the flat either on the name of 03 sibling or anyone other 02 sibling agree no issue all 03 are single and grandparents from both mother and father side dead and also we cant get any death certificate because we have no concern with them because we never went to their house and they died also they never gave there any property to my parents. we cant afford much please advise how simple the property when we sell there should be no problem and get sell easily and the property who is taking can easily transfer on his name because we 03 siblings has no objection for selling or show a simple way that house should be on our name or anyone of the sibling for that also we have no issue neither any sibling have objection on the same and then we can sell easily.