Use the preventDefault() method on the event object:

function Form() {
  const handleSubmit = (event) => {
    event.preventDefault(); // Prevents form from submitting
    console.log('Form submitted');
  };
  
  return (
    <form onSubmit={handleSubmit}>
      <input type="text" />
      <button type="submit">Submit</button>
    </form>
  );
}