Finder sidebar
Finder windows have a sidebar on the left edge that provides quick access to items you often use.
If you don’t see the sidebar, press Control-Command-S.
The sidebar is divided into four sections: Favorites, iCloud, Locations, and Tags. If you don’t see any items in a section, they may be hidden—click the arrow at the right of the section to reveal any hidden items.
To customize the sidebar, click the Finder icon in the Dock, choose Finder > Settings, click Sidebar, then select the items you want to see in each section.