Tools

Google Analytics event tracking tool

Generate the code for a custom GA4 event: an event name, the parameters you need, and the format that matches your setup.

Worth knowing

GA4 has no category, action, label or non-interaction setting. A GA4 event is a name plus parameters, and engagement is measured through engaged sessions instead.
Use one of Google’s recommended event names where one fits (for example generate_lead or sign_up). GA4 recognizes them and uses them in its reports.
The gtag and onclick formats assume the Google tag is already installed on the page.
With Google Tag Manager you also need a Custom Event trigger with the same name, and a GA4 event tag that passes the parameters on.
To see a custom parameter in reports, register it as a custom dimension or metric in GA4 (Admin, Custom definitions).