I'm happy to participate in this forum and this is my first post.
our instructor gave us an assignment to design an id using C# windows application and i don' know how to put vertical line using label or any thing
Could you clarify what you mean by an id? Do you mean something like an Identification Card?
There are a number of ways to present a line on the screen, but which one you use depends on what you are trying to acheive.
You can use Paint methods to draw directly to the form or a control, or you can use an image to show a picture of a line, or you can use a control which has a border or even a split panel.
If you can clarify your goals, i can narrow down the best tool for the job :)
So go in design mode, click on the Form and select the lightning bolt icon in the properties window. You see a list of all the event available for the form. Select the Paint event and double click it. In the event handler fill in the code proposed by adatapost(just line 3 of his code of course)