E.g. I can draw things I imagine, or describe them, or "mentally navigate" spaces I remember with ease.
I also see images in my dreams, which seems to be pretty normal for people with aphantasia, so clearly a lot of us are not unable to see things in our mind, but something is - usually - preventing it from happening while we're away. Usually rather than always because some people see brief flashes, and I sometimes think I might but I'm not sure (it's surprisingly hard to determine). I've also had exactly one experience that seems to have been in a waking state where I saw clear imagery. I say seems, because while I don't think I fell asleep, I was meditating, and while I was aware and able to manipulate the imagery, it's possible it was lucid dreaming, but it was noticeable in particular because the imagery was far clearer than when I dream.