US VISA APPLICATION THROUGH INVITATION FROM US CITIZEN OR PERMANENT RESIDENT.
NON -IMMIGRANT US VISA can be obtain through invitation method,however there a lot of factors that must be consider before starting the application.

when applicant is applying for us visa through invitation,that means the applicant know the person inviting the him or her.
The US consulate will check if the applicant is immediate family member or not ,through the surname of the person inviting the applicant.
if the surname is not the same then the consulate want to know how the applicant is related to the person inviting the applicant.
The consulate will also consider the purpose of the invitation.

Applicant have to consider the purpose of wanting to visit the US.
The consulate will consider the ties of the applicant
The consulate will valuate the applicant

According to the us non immigrant law, all non -immigrant applicant are potential immigrant ,this make consular to evaluate all applicant .
For visa processing ,for visa application,for visa consultation and visa documentation
contact Focus hilltop Travels
Mr Richard 08024995989
OFFICE: 3 oduyemi street ikeja lagos

You never check their website. ONly available space for application is till 2023. But anyway, Nigerians are patient