Drag and drop items on Mac
You can drag and drop items to do things like move or copy files and folders, add an image to an email, or move text around in a document.
Move or copy items
On your Mac, select an item you want to drag—such as an image or block of text.
Press and hold the trackpad or mouse while you drag the item to a new location.
To copy the item, press and hold the Option key while you drag.
Release the trackpad or mouse to drop the item in the new location.
Use drag and drop in the Dock and Finder
On your Mac, you can drag items you use often to the Dock or the Finder sidebar to keep them handy. When you do, an alias for the item is placed there.
Add an item to the Dock: Drag apps to the left of the separator line (in front of recently used apps, if shown). Drag and drop folders to the right of the separator line (after recently used apps, if shown).
Add an item to the Finder Favorites section: Drag a file or folder to the Favorites section of the Finder sidebar. To add an app, press and hold the Command key while you drag.
To remove an item that you added to the Dock or Finder sidebar, drag it out until you see the word Remove or the Remove icon 
. Only the alias is removed; the actual item remains on your Mac.