A Provisional Hero License is a document that allows one to use their Quirks for heroic activities with recognition from the law.
This document is obtained through the Provisional Hero License Exam.
Overview
A Provisional Hero License is a typical ID card containing the holder's profile picture and hero name.
In order to obtain this license, a student is required to pass the Hero License Exam, which is held twice a year. If they pass through the initial part of the exam, but not the final, then they may be able to retake the exam after three months.
So far, the only members of Class 1-A who did not obtain a provisional hero license are Shoto Todoroki and Katsuki Bakugo.