By default the WFA password expires after a month. This can be customized for each instance.
Digital Business Services, Professional Services, Cloud Consulting or a partner can change the default expiring password to your needs or remove it altogether.
To request it, you should create an incident via Launchpad and Specify the instance ID with the new desired expiry period. Alternatively, contact your implementation partner directly.
KBA , LOD-SF-WFA , Workforce Analytics & Planning , Problem