Check File Access Permissions
By default everyone in the team can access all files stored anywhere in that team! This is the most common type of sharing and allows quick and easy management of files between a group of people.
To check who is currently a member of a team
- Click on the 3 dots next to the title of your Team
- Click on Manage Team
- Expand the Owners and Members and Guests sections to view who has access.
To check an individual files permissions on Teams
- Locate the file you wish to check in the files tab
- Select the file and choose open in Sharepoint
- Follow the Sharepoint/Office365 guide below
Sharepoint / OneDrive
These two products are actually the same and just behave slightly differently depending on if it is your personal OneDrive or files stored in Sharepoint which are essentially just a shared OneDrive folder.
- Find the file or folder that you wish to check permissions for
- Select the file by clocking on the tick box to the left of the file name
- On the right hand side click on the manage access link
- You can now see which groups or specific users have been granted access to the document
- You can also see if anyone has created a custom link to grant people access.
For a more detailed guide on sharepoint file sharing and its settings see the following link from Microsoft.