XD is a variant of LOL in the form of kaomodzi and is used online to express laughter.
The "X" in this acronym or text emoticon represents closed eyes that laugh, while the "D" is like a mouth and reflects a broad smile or laugh. Of course, in text format, this text emoticon can be difficult to read. To see the face - turn the XD.
Перевернутий XD текстовий смайлик
So when people use XD in messages, it shows that they think something is funny or express laughter. Using this abbreviation or emoticon helps convey mood and emotions in text format.
