By default, the person who created the company will be notified by email of all requests.
If an employee has a manager, it is the manager who will receive requests and be assigned a task to review the request. If a manager is set up, only the manager will receive the requests (not the company admin).
The person who made the request will be notified by email when their request is approved, declined, or modified.
Customise Time Off Notifications and Approvers:
For additional control you can customise the Time Off Approvers for any employee. Read more here
Note: Additionally, once a request has been approved it will appear in the company calendar visible to all employees as well as your Slack channel (if configured).