When to use Test Doubles and when to use classic?

Question

Software testing

I started with simple testing, then I came across https://martinfowler.com/articles/mocksArentStubs.... I realized that this test can be rewritten in at least 3 more ways

/**
     * @test
     */
    public function Email_ValidString_ChangeShouldReturnNewEmail() : void
    {
        $newEmail = '[email protected]';
        $user = $this->user();
        $user->changeEmail($newEmail);
        $this->assertSame($user->email(), $newEmail);
    }

So what, when, why and why to apply?
Because now I'm confused.