wp_login_form

 *
 * @since 3.6.0
 *
 * @return string User registration URL.
 */
function wp_registration_url() {
	/**
	 * Filters the user registration URL.
	 *
	 * @since 3.6.0
	 *
	 * @param string $register The user registration URL.
	 */
	return apply_filters( 'register_url', site_url( 'wp-login.php?action=register', 'login' ) );
}

/**
 * Provides a simple login form for use anywhere within WordPress.
 *
 * The login form HTML is echoed by default. Pass a false value for `$echo` to return it instead.
 *
 * @since 3.0.0
 *
 * @param array $args {
 *     Optional. Array of options to control the form output. Default empty array.
 *
 *     @type bool   $echo           Whether to display the login form or return the form HTML code.
 *                                  Default true (echo).
 *     @type string $redirect       URL to redirect to. Must be absolute, as in "https://example.com/mypage/".
 *                                  Default is to redirect back to the request URI.
 *     @type string $form_id        ID attribute value for the form. Default 'loginform'.
 *     @type string $label_username Label for the username or email address field. Default 'Username or Email Address'.
 *     @type string $label_password Label for the password field. Default 'Password'.
 *     @type string $label_remember Label for the remember field. Default 'Remember Me'.
 *     @type string $label_log_in   Label for the submit button. Default 'Log In'.
 *     @type string $id_username    ID attribute value for the username field. Default 'user_login'.
 *     @type string $id_password    ID attribute value for the password field. Default 'user_pass'.
 *     @type string $id_remember    ID attribute value for the remember field. Default 'rememberme'.
 *     @type string $id_submit      ID attribute value for the submit button. Default 'wp-submit'.
 *     @type bool   $remember       Whether to display the "rememberme" checkbox in the form.
 *     @type string $value_username Default value for the username field. Default empty.
 *     @type bool   $value_remember Whether the "Remember Me" checkbox should be checked by default.
 *                                  Default false (unchecked).
 *
 * }
 * @return void|string Void if 'echo' argument is true, login form HTML if 'echo' is false.
 */
function wp_login_form( $args = array() ) {
	$defaults = array(
		'echo'           => true,
		// Default 'redirect' value takes the user back to the request URI.
		'redirect'       => ( is_ssl() ? 'https://' : 'http://' ) . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'],
		'form_id'        => 'loginform',
		'label_username' => __( 'Username or Email Address' ),
		'label_password' => __( 'Password' ),
		'label_remember' => __( 'Remember Me' ),
		'label_log_in'   => __( 'Log In' ),
		'id_username'    => 'user_login',
		'id_password'    => 'user_pass',
		'id_remember'    => 'rememberme',
		'id_submit'      => 'wp-submit',
		'remember'       => true,
		'value_username' => '',
		// Set 'value_remember' to true to default the "Remember me" checkbox to checked.
		'value_remember' => false,
	);

	/**
	 * Filters the default login form output arguments.
	 *
	 * @since 3.0.0
	 *
	 * @see wp_login_form()
	 *
	 * @param array $defaults An array of default login form arguments.
	 */
	$args = wp_parse_args( $args, apply_filters( 'login_form_defaults', $defaults ) );

	/**
	 * Filters content to display at the top of the login form.
	 *
	 * The filter evaluates just following the opening form tag element.
	 *
	 * @since 3.0.0
	 *
	 * @param string $content Content to display. Default empty.
	 * @param array  $args    Array of login form arguments.
	 */
	$login_form_top = apply_filters( 'login_form_top', '', $args );

	/**
	 * Filters content to display in the middle of the login form.
	 *
	 * The filter evaluates just following the location where the 'login-password'