If you own the business entirely by yourself and plan to be responsible for all debts and obligations, you can register for a sole proprietorship. A partnership, as its name implies, means that two or more people are held liable as business owners. Danielle Wilson, president and CEO of air ambulance transport company Aero Jet Medical and sister company United Medevac Solutions, said these two are the easiest types of businesses to form, and the only difference is the number of people contributing resources and sharing the profits and liabilities.