I'm not quite sure what you mean by 'shadow people', but it sounds like you're talking about either ghosts or dark entities.
Ghosts are beings that are stuck in limbo because they have not moved on into the light. They are often earthbound and troubled, with unfinished business. Some are dark, but not all of course.
Dark entities are beings that are manifesting dark energy and tend to shun the light. They feel dark, they look dark. It's a foreboding, uncomfortable feeling. Some of them tend to siphon energy, or create fear, or magnify pain.
Some may be human souls, but that tends toward ghosts.
Dark entities can be other things too. There are some very powerful dark entities that are not human, just as there are many powerful light entities that are not human.
It is important to take care of yourself, protect yourself. Casting a sphere/circle of light energy (force field) around yourself is a good thing to do. Maintaining a space surrounded by a force field can be very helpful. If dark entities approach and you do not want them there, you can call in the light. Some times they will go into the light, sometimes they will go away if they are not ready or willing to do that. You can magnify the light, ask for the help of light entities if you need to. They are all around us, they will help you if you ask.