To modify the storage allocation method for SharePoint sites, follow these steps:
- Navigate to the SharePoint Admin Center (https://admin.microsoft.com | Admin centers | SharePoint) and select Settings from the navigation menu on the left.
- Select Site storage limits on the Settings page.
- Select Automatic to allow SharePoint online to manage the storage automatically, or select Manual to configure the limits for each site:

- Click Save when you're finished.
Switching from Automatic to Manual for the first time will set the site's storage quota to the maximum storage size of 25 TB (regardless ...