First of all do you have an Arabic font on your computer ? and secondly do you have an arabic keyboard?
If so then the easiest way would be to go to the create menu and select the little box next to the word Text , then type in the word or words you want in the top box marked Text.Then in the Type area select polygon if you want flat text or bevel if you want 3d text and finally hit Apply or create.

If you do not have an Arabic keyboard and or font then you can select the ep curve tool and go to an Orthographic view(side view or top view) and just click points to create the letters you need.Once you have the curves created you can select them and go to the Surfaces menu and click on Bevel Plus and that will create geometry from the curves.