You can use dynamic form rules in a workflow.
On the Inputs tab, click Advanced Customization.
The Advanced Customization dialog box appears.
Click Add Rule.
To match the rule for a form, select form, and then from the list, select the state of the form.
Click Add condition, and then specify a condition using an input.
If you define more than condition, from the Match list, select whether you want to match all or any of the conditions.
Click Add action, and then select the action that you want to execute after the condition is met.