Below are the various rule actions that the gtag extension enables within Launch. If you're unfamiliar with rule actions within Launch, check out the official Adobe documentation. To setup an action, you'll need to first create your rule, then under the actions select the "Google Global Site Tag (gtag)" extension, and then select the action type that matches what you want to do. A list of actions and links to their documentation can be found below.
The actions available with the gtag extension.
This action lets you set persistent values to all accounts that send a page view or event following this action.
This action lets you send a page view server call to Google — similar to what a browser load would send if the tag were directly on the page instead of in Launch.
This action lets you send an event to Google. An event is typically an action you want to track that may or may not require a browser refresh, such as a form submission, video view, or button click.