- Open the App Store app on your Mac.
- Click Purchased in the toolbar. The Purchased tab shows all unhidden apps purchased using your Apple ID.
- Use the buttons next to each app to download, install, or open the app. Reinstalling apps doesn't charge your account again.

macOS Sierra doesn't appear in the Purchased tab. Use the Search field to find it again, then download it from the product page. Learn how to reinstall macOS.
Apps purchased on another Mac in your household can also be installed on your Mac. Open the App Store on your Mac and choose Store > Sign Out. Then return to the Purchased tab and sign in with the Apple ID used to purchase the app on the other Mac.