If you do not already have some form of logging enabled, you’ll have to retro-actively pull the data from the database. Would consider looking at the Jobs or Logs table. You could probably write some code to pull this through the API and if you are familiar with PowerShell the UiPath.PowerShell Module exists.
I would suggest configuring your logs to flow somewhere that is easily reportable and easier to access than the Orchestrator’s Web UI and limited filtering.
UiPath Insights, Splunk, ELK Stack, etc.
We send out Robot logs to Splunk and as part of the End Transaction log, it has the properties detailing how long it took the process to complete.