You can upload a scanned PDF signature page within the 'Report Editor'
From the Home dashboard and under the heading 'Operations' select 'All Jobs'
Select your Job from the list and from the Job Details screen select 'Report Editor' from the tabs at the top of the screen.
In the 'Report Editor' select 'Declaration' from the left hand side of the screen, select 'Edit' from the right hand side of the screen.
Browse for you scanned PDF document on your PC and click save.