When it's a direct assignment, you can go to the Jobs >> All Jobs >> eye icon against the job >> Assignments and see the list of candidates that the job is offered to. You can see the state/status of the assignments.
Pool adverts and Public jobs:
The Jobs >> Applications list will give you the stats on the jobs advertised via pool applications and public jobs.
You can click on the eye icon against the job from the list above to go directly to the job. To send the offer to the candidates who accepted it, you can go to the Assignments tab and take the action. More on that here.
For pool adverts, you can also go to the Pools tab on the Job Information to see who has accepted, rejected or didn't answer the advert.