In Korean, 직업이 뭐예요?, 주소가 뭐예요? and other such sentences can sound a little odd because we don't include the pronoun "your" as in English. It can sound a little like "What is (an) address" for example. 주소가 어떻게 되세요? (literally "What happens to be (your/the) address?") doesn't have the same problem and it also sounds more polite compared with using 뭐예요? which can sound a little too direct.

It is similar to asking the difference between "what is your job" and "what do you do (for work/for a living)" - they are basically the same, though the second ones (직업이 어떻게 되세요 and "what do you do for work") seem to carry a less direct / more polite nuance.