Apple - How can I rotate my signature in Preview?

I've been having the same problem, but I solved it by opening the pdf file in Preview, hitting File > Duplicate, then adding the signature in the newly created file. This corrects the orientation of the file so that Preview can identify lines and you can just click on them with the signature tool (from the Annotate/Edit toolbar) and add your signature.

This thread addresses the problem best:

https://discussions.apple.com/message/16821750#16821750

Basically the issue is with Acrobat formatting scanned PDFs in a way that makes Preview think it is rotated.

The answer above about exporting to a new PDF and then trying to insert a scanned signature in the new PDF via Preview's annotation tools works to fix the problem.

To rotate the whole image:

• Open the image file in Preview
• Click "Tools" in the menubar
• Click "Rotate Left" or "Rotate Right"

To rotate only part of the image

• Open the image file in Preview
• Select the signature part
• Hit Command-x to cut or Command-c to copy
• Hit Command-n to make a new file from the cut or copied part
• Click "Tools" in the menubar
• Click "Rotate Left" or "Rotate Right"
• Hit Command-a to select all
• Hit Command-c to Copy
• In the first document, hit command-v to paste the rotated part
• Copy and paste small background-colored areas to fill in where the original signature was