There are times when you will need to be able to find your Klei User ID (or KUID) for support or for account merging purposes. To find your Klei User ID (KUID) in Don't Starve Together:
If you are playing on Steam or WeGame: On the game's main menu screen, click on the "Account" button in the lower-left hand side of the screen > when the web browser opens, your Klei User ID will be located in the USER INFO page. Your Klei User ID will look something like this: “KU_xXxXxxxX”. 
If you are playing on PlayStation 4, Xbox One, Nintendo Switch: launch Don't Starve Together, and in the game's main menu, go to Options > More > take a picture/screenshot of the screen including your Klei ID. Your Klei User ID will look something like this: “KU_xXxXxxxX”. 