Validation defines whether an answer or choice entered in to a field in a Form meets a predetermined requirement. For example, on a Training Request Form, it may be mandatory that the User has passed probation before applying for a particular training course or event.
Super Administrators can create a field when designing the Form Template asking 'Probation passed?', with two choices - yes (meets requirement) and no (does not meet requirement).
If any data entered into a Form does not meet the validation requirements while being completed, it can be withdrawn (if the Owner of the workflow stage is the Assignee) or rejected (if the Owner of the workflow stage is anyone other than the Assignee). Once withdrawn or rejected, the Form will be marked as Failed and will not progress any further through the workflow.
When the Form is being completed, fields which have met the validation requirements will be indicated by a green tick...
...or, if they have not met validation requirements (or the field has not yet been completed) a red exclamation point icon will show next to the field.
See Add validation to a field to learn how to use the feature.