Domicile of any state depend on candidates parents from which state they belongs to if you don't have ration card you can use driving license and you can have your domicile certificate by using documents like

• Proof of residences such as ration card or driving license
• Age proof such as birth certificate, school certificate (10th admit card),       etc.
• Two passport size photographs
• Proof of identity such as an Aadhaar card (https://cleartax.in/s/aadhaar-card) , PAN card (https://cleartax.in/s/pan-card) , etc.
• Self-declaration form.
• Duly filled the application form.
• Photocopies of all documents duly attested by a government official.
• An affidavit from tahsil or court.

Hope it helps