If the kids are biological children of first wife she will have right on them. she can also claim custody for them if she wants.

Your second wife is not mother of your kids 

first wife even after divorce remains mother of your children 

Your second wife is step mother of your children 

1. your first wife is the biological mother of your kids

2. your second wife is not the mother of your kids

3. for the purposes mentioned by you, the name of the first wife as mother has to be given and not of the second wife

Dear Sir,

1.Under Sunni law the father is entitled to custody of the boy over 7 and an unmarried girl who has attained puberty and in Shia law to the custody of a male child over two year and unmarried girl of 7 years. The custody of an illegitimate child goes to the mother.

2. As per the Muslim Law, only the mother holds the ultimate right to seek her child/children’s custody under the Right of Hizanat as long as she is not convicted or found guilty of any misconduct. The father’s right of Hizanat is applicable only in the absence of an able mother.

Thank you!

1. No, your current wife is not the mother of your said three daughters daughters 

2. Your earlier wife is their biological mother as per law.

1. You can not prove that your current wife is the mother of your said three daughters by submitting any document.

2. Your divorced wife is the biological mother of your said three daughters as per law.

- Your second wife is not the real mother of the kids from first wife in the absence of any legal documents like adoption/guardianship deed etc. 

- Further, in the absence of any legal document , the first mother will remain the biological mother 

- Hence, you can approach the court for getting the direction in her favour to adopt the kids. 

- Under Sunni Law the mother is entitled to the custody of a male child up to 7 years and a female child till she attains puberty.

- Further, under the Shia law , mother has custody of male child till the age of 2 years and female child till the age of 7 years.

The children born out of your first marriage are no doubt your biological children however without your second wife legally adopts the children,m she cannot become the adoptive  mother of the children, she can remain as step mother only. 

You can make the documents to prove that she is your legally wedded wife and that she is residing with you and your children of first marriage in the same as the step mother of the children and taking care of the children jointly along with you.

You can get this certificate duly notarized from a local notary public and produce the same wherever it is required. 

Your marriage certificate proves that she is your legally wedded wife and step mother of your children 

you can execute will attested by 2 witnesses that in event of your unfortunate demise your wife would take care of your children 

The proof of your marriage with this second wife as well as the proof of kids residing with you ever since your second marriage along with your second wife would be sufficient to establish the stepmother and stepchildren relationship. 

Dear Sir

Under Muslim personal law, a step-mother does not have the same rights as a biological mother.

So the court may grant custody to the children's biological mother, if something had to happen to you.

Thank you

- You can write a WILL after mentioning the details which you want in favour of kids, in the presence of two witnesses . 

1. Biological mother will have preference over the step mother in having the custody of the children.

2. If the kids desire that they will live with their step mother, then she can claim their custody on the ground of their welfare.

There is no such legal document other than their birth certificate and you being father. She need to execute an adoption deed or you need to execute an affidavit to that effect.