Some new people to Shadowrun may be a little confused about the nature of spirits. While different traditions view them a little differently what remains the same is that spirits are beings that come from the astral. They have their own domains that they reside in, for the sake of simplicity I use the elemental of fire, earth, water and air for example. Even when a spirit of Man is called by a magician they are simply spirits that embody things of humankind. In older editions these were hearth spirits and city spirits.
Hearth spirits were the representation of the home, they could be conjured inside any building that was inhabited and used as a home. City spirits were the embodiment of the city itself. They were called within the city and often took aspects of the area they were in.
In Shadowrun there are other beings on the astral, ghosts, wraiths and most likely a lot of other oogly booglies in magic books. These are the traditional Jacob Marley type "spirits". While in some ways they work the same as the astral beings we call spirits they are different in a fundamental way. They were once living beings. The Shattergraves in Chicago are filled with ghosts for example. While a magician can banish a ghost unless something is done to give a more lasting removal it will be back...and likely kinda cranky.
Now Free Spirits add another fun aspect to those with an eye towards the astral. They were once conjured by a magician and though they somehow became free of the spiritual bond they decided to stay close to the material plane. They can take on many forms and different roles, they can be helpful or harmful, wrathful or playful tricksters and even if one looks like Elvis it was never the King.