Click here to sign up for the beta program to access macOS High Sierra early. Note: At the time of this writing, macOS High Sierra is only available in beta. You will need to restart the machine to complete the download, and you will likely need to sign back into your AppleID as well, so have your AppleID password handy. The download will begin, and it will alert you once it is completed. Click on Get, and it should turn green and ask you if you want to install the update. Since the upgrade is free, it should only say Get next to the download icon, instead of listing a price. If it isn't, type 'macOS High Sierra' into the search bar at the top right, and it should be the first option available in the search results. Called High Sierra, the new operating system is more about refinements than new features, as it aims to make your Mac more reliable, capable, and responsive while laying the foundation for future innovations in the worlds of VR (virtual reality) and AR (augmented reality). It is not compatible with 'High Sierra' (10.13), not to be confused with 'Sierra' (10.12) as asked in the original question. Once available, the link to download macOS High Sierra will likely be prominently displayed on the Featured tab in the store. But as John said, yes, Quicken 2018 for Mac runs under both Sierra (10.12) and High Sierra (10.13).
Start by clicking on the Mac App Store icon on the dock on your Mac. The macOS High Sierra download will be available through the Mac App Store.
