There have been some improvements made to the ODfB and SharePoint sharing functions.
This makes seeing who has access to the files you are about to share far simpler, so as you dont share the docuements with the wrong people.
The Share command now sends shareable links by default rather than granting permissions to specific people like the old Invite people tab. This better matches user expectations that links sent in email can be forwarded to others by default. In other words, Share does the same thing as Copy link except it enables users to send the link immediately to recipients via email.
Both the Share and Copy link commands are now default to the same permissions and use the same link settings.
Users can change settings on sharing links to one of three possible permission levels:
Anyone with this link: A shareable link that can be sent to others. It behaves like email. You can forward it to others or add people to the thread and it will work. This option does not require recipients to sign-in and hence is the most convenient for recipients. Use this for sharing content that can be freely shared with others, including people outside your tenant.
Only people in [tenant]: Users who open the link must sign-in or be signed-in to a non-guest account in the tenant. It behaves like email with restrictions on it. You can forward it to others or add people to the thread, as long as the people added are inside your tenant. If any external user gets a hold of the link, they will not be able to use it. Use this for sharing internal-only content.
Specific people: Grant permission only to the people you list. The link will only work for those people (and others who already have access to the item). If recipients want to send this link to anyone else, they need to ensure those recipients have been granted permission to the resource, otherwise the link won’t work. This option produces behavior similar to the “Invite people” tab in the old sharing UI.
Tenant admins who wish to change the default link permission can do so in the OneDrive Admin Center and the SharePoint Admin Center.
Users who want to explicitly grant permissions to an item without sending a link can do so by selecting “Manage access” and then selecting “Add people”. For example, if a user wishes to make sure that a folder can be accessed by an entire division, they may want to grant access here rather than send a sharing email to the entire division.
The new sharing UI will be rolling out in the summer on the following endpoints:
OneDrive for Business on the web
SharePoint Online document libraries on the web
Windows File Explorer context menu for sync’ed files (“Share” command)
macOS Finder context menu for sync’ed files (“Share” command)
Note: Your firewall must allow access to admin.onedrive.com in order for sharing from File Explorer and Finder to work. For more information see Office 365 URLs and IP address ranges.