encode

public static
\Bitrix\Main\Text\HtmlFilter::encode(
 string $string,
 string $flags = "ENT_COMPAT"
);

Static method converts special characters into safe HTML entities.

Parameter	Description	Version
$string	Converted string.
$flags	Flag, specifying processing of quote marks, incorrect code sequences, and used document type. Uses by default - `ENT_COMPAT`.