Not to be rude, but it would be helpful if you researched them a bit and came back with specific confusions. It's redundant to constantly go over and over stuff that has been written about many times before.
Djinn is the proper name for "genie", those guys who live in the lamps.
This sounds like a simple question, but even their definition is met with a wide range of answers, depending on whom you ask. Most can agree that Djinn are astral energies made of subtle or smokeless fire long before man walked the earth. This is, after all, how they are described in the Quran (25:27). But beyond this basic fact lies an endless sea of confusing and conflicting information.
Djinn were created with free will, just like humans. Therefore, some will choose to be good and others will choose to be bad. However, ALL will be accountable to the great creator one day for their actions.
Appearance
The word jinn translates as anything that is concealed or invisible. The Djinn are a race that have no defined physical form of their own, so they are therefore invisible to the naked eye. However, they are shape shifters who can take on the physical form of just about anything they want. Many say that they walk among us every day.
You will often see smoke when your Djinn appears, not because the smoke IS the Djinn, but because it accompanies him/her. It is simply a sign that your Djinn is nearby and ready to communicate, and signifies the presence of energy.
Djinn can also appear with orbs, streaks of light, mists or other kinds of phenomenon. It can be a big, awe-inspiring appearance, or a subtle almost-not-noticed kind of appearance. With Djinn, like people, no two are exactly alike and there are countless ways they may manifest.
Some Djinn will never manifest in any kind of physical form, but that doesnt mean that they arent there and watching you. These Djinn will generally communicate with you only during dreams or meditation. They arent any more or less powerful than other Djinn, they just choose to present themselves differently.
General Characteristics
Its important not to impose your own feelings and emotions on the Djinn. Sometimes we want to think of them like warm and fuzzy pets. If you want a warm and fuzzy astral creature then youre better off acquiring a faerie, mermaid or unicorn. Djinn mean business. Their destiny is to serve humans without emotional attachment. This doesnt mean that theyre not loyal. It just means that they dont generally make decisions based on their feelings.
Djinn were created before man, which dates them back before the time of Adam and Eve who lived 6,000 years ago. These original Djinn are Preadamites, meaning they existed before Adam.
Djinn become more powerful as they age, and can live for thousands of years. An Elder is one who has reached the highest levels of energy and is somewhat harder to find. Younger Djinn are much more common, and are perfectly appropriate for the average person.
got this from
http://reviews.ebay.com/EVERYTHING-YOU-NEED-TO-KNOW-ABOUT-JINN-GENIE-DJINN_W0QQugidZ10000000003632170
Yep they can grant wishes :) but the warning of "be careful what you wish for" really, really applies here. I think the episode of The Fairly Odd Parents where Timmy meets a genie (I used 'genie' instead of Djinn to differentiate between cutesy cartoon and the actual entity) and he wishes for an omelet. The genie plops a steaming hot omelet right into his hands, no plate or fork or anything.
Also, the movie Arabian Nights features some more true-to-mythology Djinn. They are supposedly extremely tricky and don't answer to just anyone. There is that whole thing about "setting them free" and having to be their "master" for them to grant you wishes. And you can't wish for more wishes XD
It's not just the wish. It's the entity you're wishing to. Take your time and think it through instead of "Gimme my wish." Like I said, research and develop your own judgments. The Djinn aren't going anywhere so don't rush into it.
And for amusement's sake, the song "Djinn Djinn" by Angelique Kidjo: