Parole is used to temporarily bring in persons who are otherwise inadmissible or ineligible for admission to the United States due to an emergency.
Who is eligible?
You may be eligible to apply for a humanitarian waiver if you have an emergency and there is an urgent humanitarian or significant public benefit reason to allow you to temporarily enter the United States. Anyone may file an application for humanitarian permission. If you do not have an urgent humanitarian reason for your visit, you must follow the normal processes established by the Department of State to receive a visa.
Please note.
You may not use the temporary permit to evade visa or immigration processing.
If you are in removal (deportation) proceedings or have been previously deported from the United States, you must file your application with Immigration and Customs Enforcement (ICE).
Source: uscis.gov