Copy: select the text, file, or item
Copy: press Command + C
Paste: click where you want the item to go
Paste: press Command + V
Cut: press Command + X
Paste and match style: press Option + Shift + Command + V
Copy with right-click: select the item, then choose Copy
Paste with right-click: place the cursor or open the destination, then choose Paste
Copy and paste between apps: use Command + C in one app and Command + V in another
Copy and paste files: select the file in Finder, press Command + C, then Command + V in the destination folder
Copy and paste multiple items: select them together, then use Command + C and Command + V