Dear, if you are in business and need to create income proof, prepare an income certificate with any auditor. If you are drawing a salary from your business, ensure it is reflected in your balance sheet with an auditor's assistance and create Form 16 for yourself from your organization with auditor certification.
Form 16 can only be issued by the employer to their employees. Alternatively, you might need to prepare Form 12G for income proof as a professional or consultant. Everything should be certified by an account auditor with proof of income, investment, and expenses as per the IT Act limitations. Please contact your accounts auditor for more clarity.
Regards