The Portfolio Settings section in the Studio 9 theme Customizer contains 5 options. Navigate to Appearance → Customize → Theme Options → Portfolio Settings to access these settings.

Options

• Post URL Rewrite Slug (Text) — Custom URL slug for portfolio items.
• Category URL Rewrite Slug (Text) — Custom URL slug for portfolio categories.
• Deliverables URL Rewrite (Text) — Custom URL slug for deliverables.
• Portfolio Page (Page Selector) — Select the main portfolio page.
• Listing Columns (Select) — Number of columns for portfolio listing (one, two, or three).

After making changes, click Publish at the top of the Customizer to save your settings.