To copy and paste on a MacBook Air, use these simple keyboard shortcuts:

• To copy, first select the text or object you want to copy, then press Command (⌘) + C.
• To paste, place the cursor where you want to insert the copied item and press Command (⌘) + V.

Alternatively, you can use the mouse or trackpad to right-click on a selection and choose "Copy" or "Paste" from the context menu. You can also use the Edit menu in the menu bar to find Copy and Paste commands. For cutting (which removes the item from the original location), use Command (⌘) + X. If you want the pasted content to match the surrounding style, press Option + Shift + Command + V to paste and match style. These methods are standard across most apps on MacBook Air and make copying and pasting quick and easy.