This depends on how far you are through the process. If you've got the image of the cheque stored on the computer, then you simply use Image.FromFile to load it in, get a Graphics instance using Graphics.FromImage, then use the Graphics.RotateTransform
From there you can either print it out or save it back into the file to print it later, using a graphics program. You use a PrintDocument for this, or you can use Image.Save.
PS: I edited your original question to correct a few small readability issues. If you feel that I've missed something, feel free to edit it again :)