Artifact

Artifacts are permanents which can only be played during your main phase. They represent physical items of power that any wizard can employ. They typically don't require any particular color of mana to be played and are defined as being colorless.

Activated artifacts

An activated artifact

Traditionally, artifacts in Magic represent physical objects that require activation in order to be useful. This activation cost usually consists of a colorless mana cost and tapping the artifact, making them usable only once a turn.

Effects most commonly associated with activated artifacts are colored mana generation (since they can go in any deck), small amounts of damage and card drawing.

Equipment

An equipment card

Equipment cards a subtype of artifacts. They usually don't have any effect when played, and need to be equipped by creatures. They typically provide the equipped creature a boost to power and toughness as well as some ability.

Main article: Equipment

Artifact creatures

An artifact creature

Creatures can also be artifacts. Artifact creatures can be affected by anything that would affect either artifacts or creatures. Currently, artifact creatures that are not modeled after colored creatures tend to get the creature type Golem or Construct.

Main article: Artifact Creature