Yes, you can add you signature and firm logo, Please follow below steps:

1.Take Picture of your signature from your mobile camera.
2. Now in sales assist >> settings >> firm detail >> click on image icon on upper side>> click on signature(browse your signature image)
3. Make sure Signature configuration for PDF should be “ON” from settings(PDF Configuration).
4. Now when you will create Order PDf and share it, It will have that signature will be printed (no need to write signature every time).