Copy: select the text, file, or item, then press Command + C
Paste: place the cursor where you want it, then press Command + V
Cut: select the text or item, then press Command + X
Paste without formatting: press Command + Shift + V if supported by the app
Copy and paste with the mouse: right-click or Control-click, then choose Copy or Paste
Copy and paste between apps: copy in one app, switch to another app, then paste
Copy and paste files in Finder: select the file, press Command + C, then Command + V in the destination folder
Drag and drop can also be used to move or copy items in Finder