Let’s talk about what actions are, what forms they can take, and how they relate to your character.
Action is always what your characters do to get what they want. It can be a physical action or the words they say.
What it comes down to is intention. Your characters will do or say what they need to get what they want—or overcome the obstacles that stand in their way. Action and dialogue are the same because they are both done with intention towards the goal.
If a character wants into a room and someone stands in their way, there are multiple ways they can overcome the obstacle. They can punch, sneak, threaten, negotiate, woo, or many other approaches. Throughout a story or a scene, they will try to test multiple actions to achieve their goal.
Not doing something can also be an action. Choosing not to act is done with intention. The character outside the room could wait and watch until the opportunity arose to get inside. However, if a character doesn’t do something because of an internal or external reason, then that becomes an obstacle.
Finally, the actions your characters take define them. A person who is a smooth talker won’t immediately punch someone or vice versa. They may eventually—as their character grows and changes—but it won’t be their immediate first action.
Understanding action is key to understanding your character. Want, obstacle, and who your character is are all wrapped up in it. Unlocking it will unlock your story.