Right-click on the folder you want to add a color to.

Google Drive is a cloud-based storage and synchronization service developed by Google. Learn how to upload files, videos, and others to Google Drive, share permissions, and more. Other tools in Google's suite of productivity include Docs, Sheets, and Slides, enabling real-time collaboration and easy access from any internet-connected device. Key features include file sharing, version history, robust search, offline access, and seamless organization.

Google: Color-coding Google Drive Folders