The priority date is the date that USCIS uses as a reference to inform the public whether visas are available. Visas are available considering the country of nationality of the applicant and the priority date. For instance, a U.S. citizen requests a green card for his sister. Said application was received on June 21, 1998. Currently, on November 27, 2020, the petitioner wants to know if his sister can finally complete her petition. According to the Visa Bulletin of November 2020, petitions received on or before June 22, 1998, are now available. This means that after filing the I-130 petition in 1998, this applicant's immigration process can continue now.