How to pass additional values ​​to Google Analytics Events?

Question

JavaScript

gtag('event', 'Form submission', { 'event_category': "Lead", 'event_label': document.location.href });
Is it possible and how to pass additional values ​​about the submitted form in the event (form text, data for each field, etc.)
Where to add additional values ​​to the line above? Is it possible to pass in an array?
Apparently we are talking about User events ..
How to register them correctly and where to look at them later in Google Analytics?