Overview:

File and folder permissions for team members are determined by the owner, who can assign either view or edit rights on shared items. 

Members with edit access in Teams and SharePoint can share files and folders, adjust sharing options, and grant direct access to others; however, they cannot alter existing permission levels. They may send links to individuals within the organization, those who already have access, or specific people, and can manage direct access for others.

Members with view-only access can share files and folders only with those who already have access, or by requesting permissions for specific individuals. They cannot generate direct links for sharing outside these parameters or modify permissions themselves, but they can request additional access on behalf of others, which must be approved by the owner.

For more details on your permissions for shared files, please refer to the documentation links provided below.