Google Drive/Drive for Desktop
If you are migrating from Backup and Sync, please follow the migration steps here.
Drive for desktop is an application for Windows and macOS that lets you quickly access Google Drive content directly from your operating system's file browser. Drive for desktop also automatically syncs local files and directories of your choosing to your Google Drive in the background. This allows you to continuously back up your data as you create or modify it on your local machine(s) without needing to manually upload each file to your Google Drive.
Drive for desktop can be downloaded here.