can't update word

Hello laurenbritten, 

Welcome to the Apple Support Communities. From your message I see that you're unable to update Microsoft Word on your MacBook Air which is running macOS High Sierra. 

If this information is correct, I would recommend you begin with the following steps:

1 - Quit all apps. If an app will not quit, follow these steps to force it to quit: How to force an app to quit on your Mac. 

2 - Restart your Mac: Go to the Apple menu in the top left corner of your screen > Restart. 

3 - Hold down the shift key on the left side of the keyboard as you click on the App Store to launch it. This allows the app to bypass the last saved state for the app. When the app begins bouncing in the dock, you can release the shift key. Once the app is up and running, try downloading Word again.  

4 - If you're seeing the same results, quit the App Store again, restart in safe mode and try updating Word again: How to use safe mode on your Mac. 

5 - If still occurring in safe mode you’ll need to create a new user, sign into that new user with your information, and try to update again. This article will show you how to create the new user: How to test an issue in another user account on your Mac.

All the best.