how can i update my MacBook air
how can i update my MacBook air so i con download youtube
Question marked as
What model year of MacBook Air is it?
What macOS version is it currently running?
Note that there is no official Youtube App for Mac, there are many 3rd party apps, but they are unrelated to YouTube or its parent company: Google. You can access Youtube from a web browser directly and should not need to update your Mac, unless it's running a considerably old macOS version.