Once you've created a vacancy in PeopleHR, this generates a unique URL that can be shared to start gathering applications.
We don't have a direct integration with LinkedIn, however, you're able to share vacancies on LinkedIn and other various sites by going to the vacancy URL and below Apply for this Job, there is a Share option to post this to LinkedIn and other sites.
If you want to automate the sharing of vacancies to your website or job boards, see more information about an RSS feed and Indeed and Glassdoor integration.