If you have an unregistered business, you need basic KYC documents to set up a payment gateway with Instamojo or PayU Money. Most other payment gateways work only with registered businesses, and each payment gateway accepts different sets of documents which can be known once you reach out to them.
The documents required for payment gateways in India depends upon type of business formations, namely Proprietorship, Partnership Firm, Private Limited Company, One-Person Company, and Limited-Liability Partnership. Common documents required for business formation in India is generally accepted as documentation for most payment gateways in India.
Documents include, but are not limited to, PAN Card (Personal/Company), Passport, Driving License and Voters Identification Card (EPIC) for photographic proof, and, Electricity Bill, Rent Agreement, and Bank Statement or Passbook for Office Address proof. Additional documents such as a canceled cheque may be required for the bank account into which you will be receiving payments, and bank-attested Current Account statements for the last 12 months or more, or Audited Balance Sheet with Profit & Loss Account statements for last 2 years or more may be required as financial proof.