If you're self-employed it means that you're working for yourself (as a sole proprietor, partnership, independent contractor, S-corporation).  It also, mean that you have no employees.

As a self-employed entrepreneur you have certain obligations according to the IRS.  They include:

- You have to pay social security tax and Medicare tax. 

- You are also obligated to pay income tax.

- You have to pay Estimated taxes:  If you expect to owe $1,000 or more when you file your tax then you are obligated to pay estimated taxes (social security, Medicare and income).  You have to pay estimated taxes on a quarterly basis. [https://www.irs.gov/businesses/small-businesses-self-employed/estimated-taxes]

- File Tax Report:  If your business generate a net income of $400 or more you have to file a tax report.

Visit the IRS Self-Employed website to get more details on self-employed.