As a recruiter in LinkedIn Talent Hub, you can post jobs as internal jobs so only employees of the company can view and apply to these jobs.
Internal jobs will be posted on your Talent Hub company’s internal career site and will be viewable by employees with a basic user license only. Public jobs are viewable by all candidates. Internal job postings on your company's career site will have an Internal tag in the header. Internal job postings will not be visible on the public-facing career site, even if the user has Talent Hub access. They must use the correct link, which usually is the public link followed by "/internal".
Within a project you can see if a job is posted as an internal job by the Internal job tag in the header.
In the project’s Talent pool tab, candidates that are internal to the company and have applied to the role will have an Internal candidate tag in their profile card.