Can we cite from viXra? Today I just found this website viXra.org

the paper I looked at has author name but no other info about the author such as university or work.

in addition there was no references at all?

Can I still cite this paper in my PhD thesis?
You can, without doubt, but it might not be a good idea.

The first question is, of course, if the content of the paper is good.

The second question is, if you can find a more reliable source. Given the reputation of Vixra, almost any other source is more reliable, generally speaking.

I would suspect that, most of the time, when something is posted on viXra, either the content is not of high quality or you can find comparable material elsewhere.

But if you do happen to find a gem on viXra, certainly cite it. Just be very, very certain of the quality.