The undocumented individual is aforeign national who enter the country without government permission (i.e., a visa) or, after lawful admittance, remain within the country beyond their period of authorized admission. There is an increasing number of undocumented individual all over the world according to the Pew Research Centre's 2016 report, it reported 11.3 million undocumented individual in USA itself. Refer the graph given below:

In order for a foreign national to be admitted to the state, he or she must be permissible. A foreign national can be reckonedprohibited to the state by its law & order and the Consulate. If the foreign national is deemed inadmissible, he or she cannot enter without a relinquishment of inadmissibility or a determination that the inadmissibility charge was made in miscalculation. Any foreign national who was unlawfully present in the country for more than one year or who have been ordered to be removed and who enters or attempts to return without being admitted, is inadmissible for ten or more years.