If there is any legal Order demand pending in the name of deceased assessee then the demand shall be fulfilled by their legal heirs by registering in income tax portal otherwise if there is no demand then the legal heir shall get registered and after payment of tax then the heir might get discontinued for itr filling
Frist goto efilling then my account register as representative then select new request then add and select as representative then again select a category then their appear a form types to fill up where's you have to give documents like copy of death certificate copy of the pan card of the deceased person self attested pancard copy of the legal hire legal heir certificate and summit after that you get approval from income tax department to file deceased person ITR file his itr and if there's any liability then paid after that write a application to your local officers of of tax authorities with death certificate, copy pan card, aadhar card and knowledgement receipt of filling returns to cancelled the pan of deceased person and surrender the pan card