Site scripts are JavaScript Object Notation (JSON) string files that contain the processes or actions to be executed on a site.

The JSON schema (https://developer.microsoft.com/json-schemas/sp/site-design-script-actions.schema.json) has a list of all the actions you can perform. When you create a script, the actions are executed in the order they appear in the script. Some of the common actions you can perform include creating lists, updating descriptions, activating features, modifying group memberships, executing Microsoft Flow functions, and configuring the guest access settings.

The basic format is as follows:

{
 "$schema": "schema.json",
 "actions": [
 <verbs>
 ],
 "bindata": { },
 "version": 1
};

One of the most powerful features of a site script is the ability to trigger Flow or PowerApps functions. In the following example, we're going to create a Flow function that will send out a Teams notification stating that a new site has been provisioned.