In "The Stranger," what do we learn of Meursault's work, his attitude towards it and towards promotion?
Meursault is a man of great indifference. When his mother passes away, he is neither disturbed nor particularly grieved. He tends to hold this apathetic attitude throughout most of the novel, and while he continues to live his life, he continues to lack any strong feeling about it as a whole.
This apathy is carried over to his work, which he feels obligated to do, but which he avoids particularly caring about. He tends to remain objective about things; for example, when he describes taking time off in order to attend his mother's funeral, he says,
"I have fixed up with my employer for two days' leave; obviously, under the circumstances, he couldn't refuse. Still, I had an idea he looked annoyed, and I said, without thinking: 'Sorry, sir, but it's not my fault, you know....'
Upon waking I understood why my employer had looked rather cross when I asked for my two days off; it's a Saturday today...."
His work isn't something he enjoys or dislikes. It is what he feels naturally obligated to do. The same can be said about his potential promotion; Meursault's boss speaks to him one day, offering him an opportunity to move up in the company by moving to Paris. Meursault muses,
"I told him I was quite prepared to go; but really I didn't care much one way or the other.... I answered that one never changed his way of life; one life was as good as another, and my present one suited me quite well."
His boss, naturally, is quite offended at Meursault's lack of excitement. Meursault isn't against the idea of being promoted; he simply isn't any more for it than he is opposed to it. To him, promotion or not, his life will generally remain the same because he will generally remain the same. His absurdist point of view suggests that life is generally meaningless and that he might as well just be; a promotion, a marriage, and the death of his mother are surely not able to influence him too significantly in any way.
We don't learn specifically what his job was, but at the beginning of Chapter 3, Meursault says, "There was a stack of freight invoices that had piled up on my desk and I had to go through them all." As with everything, Meursault has a relatively apathetic attitude towards his job. He doesn't like or dislike it, he just does it. In order to better understand this you might want to look into Absurdism and Existentialism. His attitude towards promotion is indifferent. When his boss offers him a job in Paris and a chance to travel he says that it doesn't really matter and that his life in Algiers is as good as it would be anywhere else. He didn't see any reason in making a life change when he was already content with things as they were.