Hi @john john Pter ,
The available size and total size shown in the image you provided cover SharePoint sites only(OneDrive and Exchange not covered).
1.To view the storage states in OneDrive:
- In the Microsoft 365 Admin Center, navigate to Reports > Storage.
- Under storage usage by product, select OneDrive.
- Review storage state column to understand whether OneDrive is below, near, or exceeding quota.
2.How to get to the mailbox usage report
- In the admin center, go to the Reports > Usage page.
- Select View More under Email activity.
- From the Email activity drop-down list, select Exchange > Mailbox usage.
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