To confirm how much storage you’re using, go to https://drive.google.com/settings/storage.
To review and delete large or unnecessary files in Drive, go to https://drive.google.com/drive/quota.
To review and delete large or unnecessary files in shared drives, go to https://drive.google.com/drive/shared-drives.
Consider deleting Drive content that you may have copied to a shared drive. If a file resides in 2 locations, it may be consuming twice the storage space.
To search for and delete unnecessary or large emails, go to Manage files in your Google Drive storage and follow the instructions for Gmail.