Actions

On each of your turns, you have three action points (AP) to spend on actions. Once you use an action, you can't use that action again until the start of your next turn unless it is marked as repeatable.

Free Action (0 AP). A free action takes negligible time or effort to perform, but usually can only be used in a limited way. The Interact action and using the Magic action to cast divine smite are examples of free actions.

Minor Action (1 AP). A minor action is relatively quick to perform. Using the Magic action to cast healing word is an example of a minor action.

Standard Action (2 AP). A standard action makes up the bulk of a turn. The Attack action and using the Magic action to cast magic missile are examples of standard actions.

Major Action (3 AP). A major action is especially intensive, using up the entirety of a typical turn. The Charge action and using the Magic action to cast fireball are examples of major actions.

No Action. Some trivial or automatic effects do not count as actions at all, and can be performed at any time. Willingly ending concentration, saying a few words, and dropping a held object are examples of non-actions.

You have one reaction that you can use to act on any turn, not just your own. Once you use this reaction, you can't use it again until the the start of your turn. Most abilities that use a reaction can only be used in response to a trigger; for example, you can only take the Opportunity Attack reaction when a creature leaves your reach.

It is possible to gain additional reactions. Additionally, some abilities are free reactions, which count as reactions but don't cost a reaction. No matter how many reactions or free reactions you have, you can never take more than one reaction on a single turn.