How can PHP be utilized to encode and decode internationalized domain names accurately for email communication?

Internationalized domain names (IDN) contain non-ASCII characters, which can cause issues with email communication. To accurately encode and decode IDNs in PHP for email communication, the `idn_to_ascii()` and `idn_to_utf8()` functions can be used to convert between ASCII-compatible encoding (ACE) and Unicode. This ensures that IDNs are properly handled in email headers and content.

// Encode IDN for email communication
$idn_encoded = idn_to_ascii('example.com');

// Decode IDN for email communication
$idn_decoded = idn_to_utf8('xn--example.com');