You could say 'business travel' for the general topic, or 'a business trip' for a specific trip.

Do you mean business travel?

Business travel

You could say... I travel for work. I am on a job/work related trip. This trip is not for pleasure. I am working on this trip. If you provide the context, sentence, it would help.

you could also say, "i am traveling on business"... it sounds strange, but it is a common statement by those who are traveling for work.