Income tax returns, Financial statement, and annual statement filing is must for every OPC. Law requires all the above-given filings. Every year you have to comply with the concerned authority. These compliances can be made online; you can file your application online on their official websites. So if you are running an OPC, then you have to comply with these filings. In the case of failure of these filings, you may have to legal problems, and you have to pay fine for these.