A group of Microsoft Products and technologies used for sharing and managing content, knowledge, and applications.
I tested this in my environment and can confirm that when App Purchases is enabled, the "From SharePoint Store" option is visible under Add an app > My apps.
Based on the information provided, I am not aware of any additional tenant-level setting.
Could you please confirm:
- Does the issue affect multiple users or only a specific account?
- Is the "From SharePoint Store" option missing only under Add an app > My apps, or is the SharePoint Store itself also inaccessible?
- Does the issue occur across multiple SharePoint sites or only a specific site collection?
If the issue is reproducible for multiple users across multiple sites and the SharePoint Store/App Purchases settings are already enabled, this may indicate a tenant-specific configuration issue or a service-side issue. In that case, I would recommend opening a support request with Microsoft so that the tenant configuration and backend service behavior can be reviewed.