The invoices without customer GSTIN will be treated and filed as non registered customer / consumer, hence cannot claim tax credit.
Input Tax Credit (ITC): Business Customers are required to submit Goods and Services tax registration number (GSTIN) before generating Invoice. Invoices cannot be modified
Under the GST system, Input Tax Credit (ITC) can only be availed on providing GST compliant invoices and accurately reporting the transaction details on the GST network.
To facilitate the same, it is critical that you update your GSTIN with us. The same will get reflected in your account in GST network (GSTR). In case your GSTIN is not updated with us, you will not be able to avail the input tax credit of the GST paid to us.
Important Note: Once the invoice is created it cannot be tampered to update GSTIN, please provide the GSTIN before creating invoice on the time of making order.