In The Stranger, there are few references to Meursault's job which, perhaps reflects his sense of apathy towards his career. At the beginning of Chapter Three, however, Meursault tells us that there "was a stack of freight invoices waiting on my desk." From this, we can infer that he works as a clerk in the shipping industry and this is supported by the reference link provided (see below).
Meursault is, evidently, good at his job and well-liked by his colleagues. In Chapter Five, for example, his boss offers him another post in the Paris office:
"You're a young man...I'm pretty sure you'd enjoy living in Paris."
But Meursault's apathy strikes again. He replies that he is not fussed about living in Paris but would take the job if his employer wished it. Of course, Meursault never takes the job in Paris and, instead, becomes embroiled in a fight with some Arabs which will ultimately bring about his downfall and demise.