This answer is for Photoshop.
To begin with, you'd really need an undistorted copy of the letterhead. Trying to edit an already distorted image is less than ideal because it will degrade the image quality quite a bit. However it could be done. You could try to use the Perspective Crop tool to undistort it first.
The example below shows use of the Perspective Crop tool (circled in red). The inset shows the result. I had to use the Perspective crop tool a couple of times to remove all the distortion.
Assuming you already have an undistorted copy of the letterhead to work with, an effective method to do something like that in Photoshop would be to turn the letterhead into a Smart Object, which you could then distort using using Edit > Transform > Distort. The Smart Object would effectively behave as a shape which could be transformed non-destructively. The tranform applied to the Smart Object will be remembered and editable at a later point. Also the Smart Object itself will remain editable - double clicking opens the Smart Object for editing.
The example below shows converting an image to a Smart Object, applying a Distort Transform, double clicking the Smart Object to open it, closing the Smart Object, then re-editing the transform.