Securely share files
There are many ways to share files with others. Not all of them are safe: free often sounds attractive, but nothing comes for free. So it is possible that your data will be viewed in terms of content.
Teams
You can of course share files securely via Teams. This is part of the Microsoft Office 365 package.
SURFfilesender
SURFfilesender is safe and does not view your data. This is therefore the safest way to send (large) files, possibly encrypted.