You can change your Full name and Display name from the menu at the following locations.
PC: Top right corner profile picture > Profile > Edit
Mobile: Bottom right corner You > Profile picture
Please refer to the following standards when changing your Full name and Display name.
Full name: Korean name English name
ex) 홍길동 Hong Gildong
Display name: Korean name/Company/Department
ex) 홍길동/SKCC/Platform Operation Group
For more detailed instructions, please refer to Changing Slack Display Name.