You need a tax professional pronto.
Once you make the decision to form an LLC, you are bound by all the laws tax laws that govern LLCs, which are different than sole proprietorships or unincorporated businesses. The penalty for not filing form 1065 is $195 per month per member.
Then, the LLC income is passed through to you not on the schedule C but on a K-1 form. For every year that you did not file correctly, you must file the form 1065 and you must file an amended personal tax return to change how you report the business income and profits from a schedule C to a K-1. If this has been going on longer than three years, you may find it impossible to get refunds of any extra tax you might’ve paid by filing incorrectly, and you will be looking at substantial financial penalties for the missing 1065s, unless you appeal to the IRS for forgiveness of the penalty. You need professional help for all of this.
