1. Open a new drawing. Click New
2. Open new drawing. Make sure you’re in 2D Drafting & Annotation workspace.
3. Type z [Space bar], type e [Space bar]. This will zoom extents your drawing area.
4. From the ribbon tools, click Rectangle
5. Specify first corner point of the rectangle at 0,0. Type 0,0 [Enter].
6. Move your cursor to right side and specify other corner point at 10,6. Type 10,6 [Enter].
7. Your rectangle is completed.
Your first corner point of rectangle could be any where, instead of input coordinate (0,0) you can point and click any where as your first corner point of rectangle.