How to find the Workflow Service URL for a SharePoint 2013 Farm using Powershell

To find the registered workflow service address for a SharePoint 2013 farm :

Add-PSSnapin Microsoft.SharePoint.PowerShell
[Void][System.Reflection.Assembly]::loadwithpartialname("Microsoft.SharePoint.WorkflowServicesBase")
$web = Get-SPSite -Limit 1 -WarningAction SilentlyContinue | Get-SPWeb
$wfm = New-Object Microsoft.SharePoint.WorkflowServices.WorkflowServicesManager($web)
$wfm | SELECT *

The above powershell commands returns the below value :

https://abc.xyz.com:12290/SharePoint/

The /SharePoint/ segment of the URL is added by SharePoint during registration process, you should not add segment to your registration URL.