Though Mersault doesn't explicitly tell the reader the title of his position, he does infer that he works in an office building in Algiers, most likely a shipping yard, that "overlooks the sea." In chapter three, for example, he says that he had to go through a "pile of bills of lading"—receipts that list the cargo of ships.

He seems to enjoy his work and describes quite a fun and relaxing atmosphere. He works until 12.30 pm before going to a restaurant with his friend and then home for a quick nap. He states that the only problem is that office can get very hot in the heat of Algiers, and it comes as a relief when he can finally leave his office and stroll home along the cool wharves.

Mersault seems a very conscientious worker. In chapter V, he almost refuses a call from a friend because he knows his boss doesn't like him making personal calls.

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.