Let's start here. There is no such thing as imaginary friend but it is a relative. Mostly children start off this way making contact with spirit beings at an earlier age, and the spirit can be any low or high level entity from any plane. It can possess their pets or them to communicate with people or follow them around. Possession means they enter you or merge with your body in order to make contact or help an individual. They exist separately of the individuals consciousness, pet, etc and influence them but have to be invited by them. Spirits don't like to give their name or eat. Most of them are subject to the same laws as everyone else. This means during possession they feel your pain and can be controlled by the individuals thoughts and mind as well as have weaknesses and antipathies such as fears that expel and repulse them. Knowing where you made first contact can establish where it came from, first contact can establish a name as well.
There are three types of spirit beings:
1)Low level, the smaller lesser entities such as fairies, gnomes, sylphs, and undines that exist in nature and that keep to themselves mostly, not just elementals but animal spirits as well.
2)The next higher are the stronger poltergeist, higher level elementals, spirit guides, angels, deities, gods and goddesses, archangels, bad spirits, demons, etc.
3)The highest Father God and Mother Goddess.
The most basic way of spirit contact is to ask your question and listen for them to answer. This can come audibly, mentally, from electronics, or someone near you. Yes tools like an Ouija board work if done correctly, and can even invite them in. It's easier to get a spirit being to come to you then to get it to leave. Know they are expelled and repelled by their apathy and fear of knowing their name or who they are, so you can know their fear. For example demons, witches, ghost, Satan, etc hate the Bible so if you start reading from it, they leave.
Possession- to know if you are possessed, close your eyes and envision the room, now look at yourself and you will see the spirit possessing you.
To contact a spirit you need to go to where they are, such as a grave place they died at or a place known for sightings, or to where they live. Undines water spirits inhabit water, so go to a creek and envision, close your eyes and see the creek as you would with your eyes open, call on them to appear and speak your desire. Make an offering to appease them, they like what they like and all spirits have their favorites so offer these to them, but if you make them mad, you will get yours, hehe.
Knowing is half the battle, I hope this helped.
-Blessed Be )O(