An explanation of various terms used in this documentation.
Actions are accessible via the Action Panel in a command. They are little functionality to control something; for example, to add a label to the selected GitHub issue, copy the link to a Linear issue, or anything else. Actions can have assigned keyboard shortcuts.
Action Panel is located on the bottom right and can be opened with ⌘K. It contains all currently available actions and makes them easily discoverable.
Commands are available in the root search of Raycast. They can be a simple script or lists, forms, and more complex UI.
Extensions add functionality to Raycast. They consist of one or many commands and can be installed from the Store.
Manifest is the package.json file of an extension. It's an npm package mixed with Raycast specific metadata. The latter is necessary to identify the package for Raycast and publish it to the Store.