All changes to the workflow are captured in the Audit log table of the database (BPAAuditEvents). Different categories of events are captured in the sCode column of the table, for example a successful login event has the sCode L001 and modifying a process has the sCode P004. You can obtain the list of sCodes from Customer support - see this article here
https://portal.blueprism.com/customer-support/support-center#/path/Installation-Platform/Security/Audit/1211701332/Which-Blue-Prism-Actions-and-Events-are-audited.htm.
By default, this audit logging is enabled by default and cannot be turned off. Custom logging cannot be added to the BPAAuditEvent table directly. You can log anything that you want from inside a running process by implementing your own logging solution, but those won't log the actions taken inside the Blue Prism GUI software itself, as those are handled automatically.
There isn't any in-product functionality that would allow you to redirect those logs to the Event Log. What I would recommend would be to, from a database level, regularly select the results of the BPAAuditEvent table, and use some custom scripts to import them to the Event Log. Or you can export the Audit Events from the command line interface using the "getauditlog" flag, for example:
c:\%Blue Prism Installation Folder%> Automatec /getauditlog /from 20181001 /to 20181031 /user username p@ssword
Then you can also write a script to process the text returned from the /getauditlog command and push that data into the Windows Event Viewer.