There are five different attack methods in Champions Online. These describe what action the player must take in order to use the power.
Click abilities need only be clicked once on the action bar by the mouse, or the associated key pressed, in order to activate. A click ability will not have a charge option. (Example: Snap Shot)
Tapped abilities are mechanically identical to click abilities, however tap abilities also have another activation option (usually charge or maintain). (Example: Gigabolt)
Charge Up powers require the mouse button on the power’s icon or keep the assigned number key pressed to charge a power. Generally, the longer a power is charged, the more damage it does and the more energy it requires. The power can be activated at any time during the charge by releasing the power key, but it will activate automatically when fully charged. Some charge up powers can also be fired with a tap for a quick burst of damage while others require that the power be held for its full charge for any effect to occur.
Example: Sniper Rifle
Maintain powers start with charge bar full and require the mouse button on the power’s icon or keep the assigned number key pressed for a duration. The power will remain active until the charge bar empties, insufficient energy or the power key is released. Most maintain powers have a maximum maintain time, and many increase in strength later in the maintain. Maintain abilities have their effect for the duration of the keypress/click. Usually the effect occurs on regular intervals, or periods. Some maintained abilities lockdown the champion, preventing them from moving as long as the power is maintained. If there is sufficient energy, the power can be reactivated by pressing the key again.
Example: Heat Wave
Toggle abilities don't require the key/click to be held, they are turned on by a tap but continue with no further interaction. Many have a maximum duration or effects at regular intervals, similar to a maintain ability. (Example: Mini Gun)
See main article: Slotted Passive
Slotted passives require only that you put the ability into your passive slot. You may only have one active at a time, however you may have multiple slotted passives, each active in a different build. (Example: Fiery Form)
See main article: Energy Unlock
Innate passives require no interaction whatsoever by the player. If they take the ability, it is then always on. Only one of these powers may be chosen per champion. (Example: Telepathic Reverberation)