You can adjust the settings of your leave policies to restrict employees from requesting leave during their probation period. To do so follow the below steps:
Under Settings, click on Configuration, select the Time Off tab and click on Time Off Policies
Click on the Edit icon to edit settings of the leave policy you wish to restrict
Click on the restrict during probation option
All employees under probation (if the probation date on the work profile is filled in) will be notified at the time of request that they are unable to apply for this type of leave as they are under probation.
Click here to learn more about updating the probation dates on employee profiles.