When a person decides that his/her business will not be seperate from him (a seperate entity) he may want to become a sole proprietorship. This type of company means that everytime the owner makes a sale or provides a service, he is doing so for his own profit. This person who is making the profit will be required by the IRS to file a Scedule C which is a "Profit and Loss from a Business" statement, in addition to his or her regular income tax. This document explains your income and your expenses during your sole proprietor year in business.
Additionally, the person who is a sole proprietor also takes on all of the liabilities of the company, meaning if the money is not available within the company, the person will need to pay for it, and the creditors you owe may come after your income or your assets. In most cases people are unaware of this and they will find that if the company is losing money that they will need to pay back all of its debts.
The sole proprietor may not have other people that they need to make the tax statement for, but he must be aware of his own and how the business is doing. Additionally when he files for a business loan, he must show proof of capitol, credit and what ever paperwork they may require. He will also be responsible even if the business cannot meet its obligations which means that his home and other assets could be in jeapardy of being foreclosed for non payment.
Another thing that is important to remember is that the sole proprietor has no partners in which to share his income with, so all profits, whatever they may be will belong to him.