open a PDF or image
There are several ways you can open PDF documents and image files (such as PNG files) in Preview.
From the desktop or Finder: Double-click a file. You can also select one or more files, then choose File > Open With > Preview.
From within Preview: Choose File > Open, locate and select one or more files, then click Open. If you worked on a file recently, you can choose File > Open Recent, then select the file.
From iCloud: Click iCloud Drive in the Finder sidebar, then double-click a file to open it. For more information about iCloud Drive, see the Apple Support article Set up iCloud Drive.