Based on the level of respect or formality, you can say "Where do you work?" in Korean in 3 ways:

• Informal: neo-neun eodi-eseo il-hae? (너는 어디에서 일해?), neo-neun eodi-eseo il-hani? (너는 어디에서 일하니?)
• Formal: dangsin-eun eodi-eseo il-haseyo? (당신은 어디에서 일해요?), dangsin-eun eodi-eseo il-hapnigga? (당신은 어디에서 일합니까?)
• Very Formal: dansin-ggeseo-neun eodi-eseo il-hasipnigga? (당신께서는 어디에서 일하십니까?)

- where: eodi (어디), eodi-e (어디서), eodi-eseo (어디에서)
- you (subjective): neo-neun (너는), dangsin-eun (당신은), dansin-ggeseo-neun (당신께서는), ne-ga (네가), ni-ga (니가)

Please refer to How to pronounce Korean Alphabet for the English pronunciation in this answer.