An individual in the United States with F-1 status is here to study full-time at a college or university and has plans to return to their home country after they complete the program. They must be accepted into a program before applying for this status.
Nonimmigrant status refers to the fact that the person does not plan on staying in the United States on a permanent basis. In fact, they have to maintain a residency in their home country and demonstrate that they have strong ties to their home country, in addition to demonstrating that they will be able to support themselves while they are in the country in order to be considered for F-1 nonimmigrant status.
Strong ties could include family members or an offer for a job after completing the education program they seek. F-1 students have 60 days grace period after the end of their studies to make plans to return to their home country.