The Future Sight
symbol for Enchantment cards.
Enchantments represent persistent magical effects, usually remaining in play indefinitely. Most have continuous or triggered abilities, but some have abilities that can be activated by their controllers.  
Formerly, enchantments were one of two types; enchant permanents (now Auras) or global enchantment.
Now, the term "global enchantment" is not officially used anymore, but other subtypes of enchantments have come into existince. 
Enchantments that possess the rules text "Enchant" are of the Aura subtype. These enchantments must be attached to an object specified by the Enchant ability, and exert an effect on that object.
An Aura's text box will specify what kind of permanents it can be attached to, reading "Enchant [type]." When an Aura spell is played, it must target an appropriate permanent, and when it resolves, it comes into play attached to (and no longer targeting) that permanent. If the permanent it is attached to leaves play at any time, becomes a type that the Aura cannot enchant, or gains protection against any of the Aura's characteristics, the Aura becomes unattached and will go to the graveyard.
Curses are Aura enchantments that possess the rules text "Enchant player". Curses were introduced in Innistrad and featured in the Innistrad block and Commander 2013.
Although all Curses enchant players, not all enchantments with "Enchant player" are Curses. In fact, the ability has been featured on cards from previous expansion sets, such as Psychic Possession from Dissension.
Shrines are non-Aura enchantments that possess an ability that is triggered at the beginning of its controller's upkeep. The effect is proportional to the number of Shrines that player controls. Shrines were introduced and featured in Champions of Kamigawa only, and all Shrines possess the legendary supertype.
Enchantment creatures and enchantment artifacts
The Theros block had a "enchantment matters" theme and introduced enchantment creatures and enchantment artifacts. 
From the Comprehensive Rules (Khans of Tarkir)
- 303. Enchantments
- 303.1. A player who has priority may cast an enchantment card from his or her hand during a main phase of his or her turn when the stack is empty. Casting an enchantment as a spell uses the stack. (See rule 601, "Casting Spells.")
- 303.2. When an enchantment spell resolves, its controller puts it onto the battlefield under his or her control.
- 303.3. Enchantment subtypes are always a single word and are listed after a long dash: "Enchantment — Shrine." Each word after the dash is a separate subtype. Enchantment subtypes are also called enchantment types. Enchantments may have multiple subtypes. See rule 205.3h for the complete list of enchantment types.
- 303.4. Some enchantments have the subtype "Aura." An Aura enters the battlefield attached to an object or player. What an Aura can be attached to is restricted by its enchant keyword ability (see rule 702.5, "Enchant"). Other effects can limit what a permanent can be enchanted by.
- 303.4a An Aura spell requires a target, which is restricted by its enchant ability.
- 303.4b The object or player an Aura is attached to is called enchanted. The Aura is attached to, or "enchants," that object or player.
- 303.4c If an Aura is enchanting an illegal object or player, the object it was attached to no longer exists, or the player it was attached to has left the game, the Aura is put into its owner's graveyard. (This is a state-based action. See rule 704.)
- 303.4d An Aura can't enchant itself. If this occurs somehow, the Aura is put into its owner's graveyard. An Aura that's also a creature can't enchant anything. If this occurs somehow, the Aura becomes unattached, then is put into its owner's graveyard. (These are state-based actions. See rule 704.) An Aura can't enchant more than one object or player. If a spell or ability would cause an Aura to become attached to more than one object or player, the Aura’s controller chooses which object or player it becomes attached to.
- 303.4e An Aura's controller is separate from the enchanted object's controller or the enchanted player; the two need not be the same. If an Aura enchants an object, changing control of the object doesn't change control of the Aura, and vice versa. Only the Aura's controller can activate its abilities. However, if the Aura grants an ability to the enchanted object (with "gains" or "has"), the enchanted object's controller is the only one who can activate that ability.
- 303.4f If an Aura is entering the battlefield under a player's control by any means other than by resolving as an Aura spell, and the effect putting it onto the battlefield doesn't specify the object or player the Aura will enchant, that player chooses what it will enchant as the Aura enters the battlefield. The player must choose a legal object or player according to the Aura's enchant ability and any other applicable effects.
- 303.4g If an Aura is entering the battlefield and there is no legal object or player for it to enchant, the Aura remains in its current zone, unless that zone is the stack. In that case, the Aura is put into its owner's graveyard instead of entering the battlefield.
- 303.4h If an effect attempts to put a permanent that isn't an Aura, Equipment, or Fortification onto the battlefield attached to an object or player, it enters the battlefield unattached.
- 303.4i If an effect attempts to put an Aura onto the battlefield enchanting an object or player it can't legally enchant, the Aura remains in its current zone.
- 303.4j If an effect attempts to attach an Aura on the battlefield to an object or player it can't legally enchant, the Aura doesn't move.
- 303.4k An ability of a permanent that refers to the "enchanted [object or player]" refers to whatever object or player that permanent is attached to, even if the permanent with the ability isn't an Aura.
- ↑ Mark Rosewater. (June 25, 2007.) "Enchantment For Better Things, Part One", Daily MTG, magicthegathering.com, Wizards of the Coast.
- ↑ Mark Rosewater. (July 02, 2007.) "Enchantment For Better Things, Part Two", Daily MTG, magicthegathering.com, Wizards of the Coast.
- ↑ Aaron Forsythe. (June 29, 2007.) "Enchanting Discourse", Daily MTG, magicthegathering.com, Wizards of the Coast.
- ↑ Sam Stoddard. (May 02, 2014.) "Making Enchantments Matter", Daily MTG, magicthegathering.com, Wizards of the Coast.
| Card types
|| Card types
|| Equipment, Fortification, Contraption
|| Aura, Curse, Shrine