When working with forms in React, you need a reliable way to process the data users enter. React Hook Form provides a special function called handleSubmit that you use to manage what happens when a form is submitted. The handleSubmit function is a key part of React Hook Form's workflow. You wrap your own submission handler function with handleSubmit, and then pass this wrapped function as the onSubmit prop to your form element. This ensures that React Hook Form takes care of gathering the form data and running validation before your handler is called.

The main job of handleSubmit is to collect all the current values from your registered form fields, run any validation rules you have set up, and, if everything is valid, call your submission handler with the collected data. This means you do not have to manually prevent the default form submission behavior or extract values from the event — React Hook Form does it for you.

After the form is submitted and validation passes, your submission handler function receives the form data as its argument. This data is usually in the form of a plain JavaScript object, where each key matches the name of a form field and each value is what the user entered. You can then use this data to do anything you need, such as sending it to an API, saving it to state, or displaying it on the screen.

Using handleSubmit makes it simple to manage form data and ensures your forms behave consistently and reliably.