There are 3 groups of Users who can add candidates by Direct Sourcing.
Super Users.
Recruiters.
Direct Sourcing has to be enabled on the Position, to do this:
Open a position.
Click Edit.
Expand the Publication section.
Ensure Direct Sourcing is ticked.
Once ticked, the Direct Sourcing section will appear, allowing you to set the publication date and and closing date, and Application process and Selection Process.
Click Continue to save your settings.
If the User is not a Super User or a Recruiter you will need to go to:
Config. User Admin.
Locate the User.
Click Edit.
Tick Recruit or Super User as appropriate under the Access tab.
Save the User's settings by clicking Update User at the bottom left.