Do you know about outsource, offsource, freelance please help me?

What is the kind of job that the companies want to employ the foreign employess (such as; US company employee Vietnamese employees for low wage) for drawing graphic, 3D, CAD. Is it outsource or offsourc or freelance…I am confusing 3 of them, can you diffrentiate them for me. I want to find some websites that provide the information about the company want to find the foreign employee to draw graphic, 3D, CAD or something which is related to designing. Can you give me some links. Thank u very much