1. Open the form library, Go to Settings-> Form Library Settings
2. Click on Workflow settings->Add workflow
4. After setting the workflow configuration, go to Form library settings again and click on Information management policies setting under Permissions and Management section.
Click on Define policy
Click on checkbox Enable expiration . Select the field (e.g. Created) and time period(e.g. 3 Months).Select the action “Start workflow” and set the “Archival workflow”.
5. Done with the settings, now archival policy is ready.