Where to store a file?
Is it personal to you, you want to keep it confidential or you want to work on it before sharing with others?
One Drive - e.g. your Desktop or Documents
There is no harm in storing files in a personal location when appropriate. Anything stored in OneDrive are private to only you (unless you share them). The downside is that your colleagues or team will not be able to benefit from the work you store here. This is especially noticeable when staff leave the School. Where possible you should always store documents in an appropriate shared location.
Is it to be shared only with specific group or team?
Specific Team
For example when working on a new SOW or a proposal for a trip, it is best to store this in your department area's. This ensures that the file is immediately available to the rest of your team (should anything happen to you) and makes sure that it is stored appropriately. Any new members of staff that join your department or team will then have full access to all the existing files that the team/department have been working on.
You want to allow anyone in the School to see it?
All Staff Team
Sometimes you just need everyone to see a document. There are specific places on the S drive for documentation that everyone should be able to access. Likewise you might want to share the end of term arrangements with the whole School. Why not create in the School Office Team/Sharepoint area and then share from there with all staff? That way all the old term arrangements are stored together for School Office to manage, but all staff can still access the latest version. No need to email the file to everyone, just send them a link.
You want to share a file with someone external to the School?
Store the file as per above options and then share it using Office 365 or Foldr if its on the S: Drive
There are two ways of achieveing this. The easiest by far is to store the file in Office 365 (either OneDrive or Teams) and then using the share button next to the file, create a public link that you can email to anyone outside of School. You can destroy the link at any point (in fact by default any public links will expire after 90 days)
Alternatively if the file or folder is on the local network drives, you can use folder to create a public link in the same way. In addition you can add a one time password and choose when the link expires.