There are basically four types of entities that can be selected for a company: sole proprietorship, corporation, partnership and Limited Liability Company (LLC).
Sole Proprietorship- This is the simplest form of business entity. No additional paperwork is required for formation, just start a business and go. The taxpayer would fill out a schedule C on their tax return and that is essentially it. This type of entity however has no liability protection and the taxpayers assets can be at risk in the event of a lawsuit.
Corporation- For tax purposes there are two types of Corporations a C Corporation and an S Corporation, named as such because that is where they are explained in the IRS Code (Chapters C and S). A C corporation is taxable as a separate entity unto itself. The advantage of a C Corporation are certain liability protections for the owners. The C corporation falls short in that it has a double taxation problem in that the corporation pays tax and then the shareholder(s) (you) pay taxes on the dividends that it pays you.
An S Corporation is treated as a flow through entity which simply means that the corporation does not pay taxes, the income flows through to the individual owners to pay the income tax on. This is a simple election that happens when the Corporation is formed. Advantages of an S-Corp are: protection of a C corporation and income taxes are paid at the individual level.
Corporations can be complicated due to the rules that have to be followed to maintain their status, such as annual meetings at which minutes are taken (even if there is only one shareholder, etc.)
Limited Liability Company (LLC)
LLC’s are entity’s that were originally created in Wyoming and now are available in most states. The LLC allows liability protection similar to a C Corporation, but the flow through advantages of the S Corporation. The “owner” of the LLC simply completes a schedule C on their individual tax return to pay the tax on the income generated by the LLC. Advantages are that it makes tax preparation easier usually, you don’t have to pay to have a separate return completed, and liability protection. The disadvantages happen as you become larger and add more owners to the situation, which you then have to file a partnership return and each individual pays tax based on the income from a k-1 and all income is subject to self employment taxes.
Partnership
This form of business is similar to the sole proprietorship (except in the case of a Limited Partnership, but even then somebody is on the hook). Partnerships should have an agreement on percentages of ownership and profit percentage, and particularly a written way out of the partnership. This helps to take the emotion out of the business. Of course this is not totally possible, but if there is no partnership agreement then expect nothing but bad things to happen.
Entity selection is very important so talk with your accountant or attorney to help you through the decision process.