As an employer, in order to qualify to petition a foreign worker, you must prove that there is indeed a shortage of workers in your industry or geographical area, prompting you to hire an international worker instead. Additionally, the need for their service should only be one year. If there is a need to extend, another petition should be filed. Maximum possible visa extension is up to 3 years but the request to extend should be done in a yearly basis.
On the other hand, if you are an employee, you should be qualified to work temporary in the United States as a non-agricultural worker. Most importantly, you must show and prove your intention to return to your home country as soon as the visa expires. If there is a need to extend, your employer should file a petition for you. Otherwise, you have to return to you country after a year only.