XD is the variant LOL in the form of kaomodzi and is used on the Internet to express laughter.
The letter "X" in this abbreviation or text emoji represents closed eyes that are laughing, while "D" resembles a mouth and displays a wide smile or laughter. Of course, in text format, this text emoji can be hard to read. To see the face - flip XD.
Перевернутий XD текстовий смайлик
Thus, when people use XD in messages, it shows that they find something funny or are expressing laughter. Using this abbreviation or emoji helps convey mood and emotions in text format.
