To add to what Andi said, it also depends on the size of the job you are doing. In a normal office environment you will carry out your everyday tasks. Should your boss ask you to do something that will require a large amount of work and many days it is considered an assignment.

Hello, just to say you cannot say - If I mention to my works, is that right to call my works "tasks" or "assignments"? It is not correct English. I think you mean something like, If I am talking about what I do/the work that I do, can I call them tasks or assignments? You would not say works as it is plural. You can say I have some assignments to do, but only really if you are studying. You can say, I have some projects to do or some tasks to complete, depending on what you are doing. If you work, it is more natural to talk about what you do. For example, What do you do? (Meaning what work or study do you do? Are you busy? Yes I have a lot of work to do. I have a lot of things to do at work. I need to finish a lot of work. I need to finish/complete some urgent tasks. Which one is more common be used? Or are there any better words then these ones?

If I mention my work, is it correct to say "tasks" or "assignments"? In your work, Ruby, it is correct to use both. Let me give an example; I work as a web designer, and each client has an assignment for me, for example a project to design their home page, and I divide the assignment into tasks, such as designing the header, menu, content area, and footer. My price can be for the assignment, or the client can pay for individual tasks.