Fax app uses a standard scanning library that is also used by all other Fax type apps. The Faxes should be of high quality as long as you provide the app with a clear image of the document you want to scan.
If you are in a dark area, you need to try provide sufficient lighting onto the document to be able to see details clearly. If you are using this at night or in a dark area, try taking a picture again with flash turned on to see if it helps.
After scanning, if you notice that the top part of the document has been cropped or cut off, this is not true and the image is actually covered by our pop up dialog box. The image will be sent with the same dimensions as you had taken them without any cutting off or cropping.
If you still have any further fax quality issues, please contact our support team, and we will help to investigate into it.