An internal user when send email to our support address, a case is created and assigned to a queue (email-to-case). I want Salesforce to pull certain fields (eg: department) from user record and publish into a custom field on the case record. I've tried process builder & WF rule but not able to create logic. (just for ref web email and web name contains correct details of the user and matches to the user record within Salesforce). Any help would be really appreciated.
Email to Case is a tough one because it runs as a specific user, I believe, not as the user who is creating the email. So you have no way of linking the Case to the user who submitted it without using either Flow or a trigger to look-up the matching User with the email address and then to populate fields from that. So the solution would be to use a before insert trigger or a flow to populate the field. You may also be able to use Process Builder to kick it off, and to pass the CaseID to an Apex class or a Flow.