Create a Saved Workflow History Search

Workflow History is not available as Search Type if you create a New Search when navigating to Lists > Search > Saved Searches > New.

To create a Workflow History Search:

1. Create a new search for another type: List > Search > Saved Searches > New > Select any standard record (i.e. Customers, Account, etc)
2. Change "searchtype" parameter in the URL to "WorkflowHistory"

OR

Paste this URL : https://system.netsuite.com/app/common/search/search.nl?searchtype=WorkflowHistory&rectype=-1

Note: You have to spell "WorkflowHistory" as it appears here; otherwise, the url won't work.