Regarding Legal representative

Sir with due respect I want to know that that the income tax case of my husband was fixed for secrutiny by issuing notice 148(A) on account of cash deposit in his Cash credit account and saving bank account in which he has deposit cash more than 60Lac out of his trading business of footwear.Sir in response of notice issued under section 148 my husband was filed his return under section 44 AD by showing profit more than 8% and proof regarding sales/turnover uploaded the vat and GST returns and required documents what as on last hearing my husband has been expired and he was the sole proprietor of the firm.Sir now I want to know what is the procedure to make the Legal representative (LR) and will be the responsible to carry on the proceedings initiated against the deceased assessee.Thanks.