
Hi @Penny007 ,
- The permissions of SharePoint are available at each level.
The button to share the site in the upper right corner is to control who can invite permission in this site.
The three points share is to grant permission for specific files.
- If you do not enable Check in/Check out, you will see each other when editing together.
For more information, please refer to:
https://learn.microsoft.com/en-us/sharepoint/external-sharing-overview
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