By default, when a time off request is submitted by an employee, their manager will see the following notifications that a request has been submitted and requires approval.  

1. A notification in the Workflow section
2. An entry in their calendar

The manager will also receive an email notification telling them that one of their employees has submitted a time off request.

 By default, if the manager does not action the request i.e. Approve or Decline, they will receive two further reminders. The first reminder will be 3 days after the submitted date

And the second reminder will be 7 days after the time off request submitted date

The settings for these reminders can not be changed or modified, but can be set in a workflow as escalations which is why we allow turning off the default reminder option. To do this go to:

Administration > Company > Settings > Company settings > Notifications

 Then select 'Disabled' from the 'Default timeoff approval reminders' dropdown.

Click here to read about setting escalations as part of a workflow.