Before you can task Gemini with cleaning up your Google Drive, there are a few requirements worth noting. First, you'll need a Google AI Pro or AI Ultra subscription. The feature isn't available to free accounts, which means it will not appear in Google Drive's interface if you aren't already a paid user.
If Google Drive is your primary cloud storage, this requirement is not the worst thing to spend your money on since the AI Pro subscription, priced at $20 per month, comes with 5TB of additional space and a YouTube Premium Lite subscription (amongst other things).
Organize My Files in Drive is also available to Business, Enterprise and Education customers, but keep in mind you won't be able to use your workplace account to organize your personal files. Additionally, you can't use Gemini to organize files and folders you share with your colleagues. The feature only works with private folders.
Next, you need to enable Smart features in Google Workspace. This setting is enabled by default in most markets where Google offers Workspace. If you're unsure if smart features are active on your account, here's how to check: