Visitation Dreams, have any of you experienced one?

I have had some of these experiences too. I don’t tell people because they think you are imagining things but perhaps a lot of us are like that and the experiences are more common than I thought.

So, is a visitation a dream, or something that happens, or someone you see when awake, please?

Several times.
When I was in ICU a few years ago, my parents appeared( while I was still unconscious) and walked with me, taking my hands, down a long corridor, then they pointed back the way we had come and I understood that I had to go back and that my time to die (which was a real possibility) had not come.
I found it hugely comforting and 100% believe the spirit lives on. There have been other examples but that was the most poignant one for me.

My mum told me she had nodded off on the sofa, and woke to see her late sister, surrounded by a sort of glow.
She said her sister looked beautiful and serene.

Manifestations of wish fulfillment, nothing more.

I have very vivid dreams these days. I’ve lost so many dear friends over the past few years and my dreams are full of them.

I tend to think they are figments of my own longing

I believe this to be true of the many "visitation" dreams I have had of my grandmother. As a child and young woman some of my happiest and most contented hours were spent sitting chatting to her while we both did a piece of sewing, crochet or handwork of some kind.

My grandmother died before I applied to uni as a mature student. However the day I graduated I had a "waking dream" of her sitting on the front row looking proud as I went up to collect my diploma.

There were many secrets in our family which I often think about at night in bed when its quiet. These are the times when I am most likely to have a "visitation" from grandma.