You can view and edit custom fields used by Vacation Manager plugin in Custom Fields section in Vacation Manager Configure panel.
...
Custom fields used by Vacation Manager
Chart - displays statistics in a pie chart form, with selected and available vacation days,
Teams - labels field
Period type field - radio button where user can select period type,
Start/End date pickers - date pickers where user can select start and end date of an absence. Those fields are used internally for calculating used days,
Start time pickers - date time picker where user can select start time of an absence. These field is used internally for calculating used days,
Time period picker - minutes picker where user can select time of absence,
Half of day - radio button field where user can select half of day,
Supervisor field - single user picker with supervisor selected by reporter. Supervisor will be able to review and accept vacation request. After manually editing this field, you must configure this field to filter only users from Supervisors group,
Substitute person - single user picker, contains information about coverage person on reporters absence,
Used vacation days - number field with vacation days used by vacation request. This field is automatically calculated,
Used vacation minutes - number field with vacation minutes used by vacation request. This field is automatically calculated.
Changing field and migrating data in existing Vacation Documents
...
Warning: This operation will overwrite all existing data in newly selected custom field in every Vacation Document.
...