The United States has resumed its drop box (visa) application in Nigeria.
The reintroduction of the drop box service or interview waiver in Nigeria has been announced by the US Embassy in Nigeria.
The Drop Box visa renewal program allows eligible visa applicants who have previously been granted a visa to the United States to renew their visas without having to go through an interview.

Applicants who have already been granted a visa to the United States may seek to renew their visas without having to go through an interview.

See classifications: https://oclocknews.com/drop-box-visa-application-resumed-in-nigeria-us/