I have a date field that, when changed, I'd like for an update to another field specifying which Salesforce User made that change. Would the best way to go about this be a Workflow Field Update? How can I create the field update to a lookup field? Essentially, when this date field is actioned, I'd like for the secondary field to have the User's First and Last name populated in it and linked to their User Profile, as any lookup would be.
The basis of this request is we want that when a specific person (one who has permission) edits a field on the custom object, that the date and that User's name is captured. This would ideally be similar to the Last Modified by field, but only for certain users.