Source

File: wp-signup.php

function show_user_form( $user_name = '', $user_email = '', $errors = '' ) {
	if ( ! is_wp_error( $errors ) ) {
		$errors = new WP_Error();
	}

	// Username.
	echo '<label for="user_name">' . __( 'Username:' ) . '</label>';
	$errmsg = $errors->get_error_message( 'user_name' );
	if ( $errmsg ) {
		echo '<p class="error">' . $errmsg . '</p>';
	}
	echo '<input name="user_name" type="text" id="user_name" value="' . esc_attr( $user_name ) . '" autocapitalize="none" autocorrect="off" maxlength="60" /><br />';
	_e( '(Must be at least 4 characters, letters and numbers only.)' );
	?>

	<label for="user_email"><?php _e( 'Email&nbsp;Address:' ); ?></label>
	<?php
	$errmsg = $errors->get_error_message( 'user_email' );
	if ( $errmsg ) {
		?>
		<p class="error"><?php echo $errmsg; ?></p>
	<?php } ?>
	<input name="user_email" type="email" id="user_email" value="<?php echo esc_attr( $user_email ); ?>" maxlength="200" /><br /><?php _e( 'We send your registration email to this address. (Double-check your email address before continuing.)' ); ?>
	<?php
	$errmsg = $errors->get_error_message( 'generic' );
	if ( $errmsg ) {
		echo '<p class="error">' . $errmsg . '</p>';
	}
	/**
	 * Fires at the end of the user registration form on the site sign-up form.
	 *
	 * @since 3.0.0
	 *
	 * @param WP_Error $errors A WP_Error object containing 'user_name' or 'user_email' errors.
	 */
	do_action( 'signup_extra_fields', $errors );
}