Final answer:
The appropriate tool for customizing the logo, theme, and title of the HR Service Portal is the Branding Editor, which offers control over global visual elements to align with organizational branding.
Step-by-step explanation:
The configuration option used to customize the logo, theme, and title of the HR Service Portal in ServiceNow is the Branding Editor. This tool allows administrators and designers to tailor the look and feel of the portal to match the organization's branding guidelines. With the Branding Editor, you can change elements such as the portal logo, the color scheme (theme), and the browser title that appears on the tab. The Branding Editor is a part of the portal's settings where more global visual aspects are controlled, and it differs from the Page Editor or Widget Editor that handle more fine-grained customization of individual portal pages or components.