Module 2 of StartCloud's Microsoft 365 Everyday Skills learning pathway, in five short units with a knowledge check: why an emailed attachment becomes an uncontrolled photocopy, how to share a link instead and choose between specific people, people in your organisation and anyone with the link, working on one document at the same time with coauthoring and comments, and using version history to recover an earlier version without keeping safety copies.
Stop Emailing Attachments
The photocopy problem
You have almost certainly lived through this one. A quote goes out for review as an attachment. Two people reply with changes, each working on their own copy. Somebody forwards it to a third person who was not on the original. A week later there are five versions and a genuine argument about which one went to the client.
The moment a file becomes an attachment, it stops being the file and becomes a photocopy. Every reply makes another one, and none of them know the others exist.
You have created a copy and lost control of it. You cannot update it, cannot take it back, and cannot tell who has it. If the numbers change tomorrow, everyone is still looking at yesterday's figures and nobody knows.
There is one file. Everyone opens the same thing, so everyone sees the current version. You can change who has access afterwards, and if the numbers change tomorrow the link still points at the truth.
Quoting an old price. Sending a client a document with the previous client's details still in it. Working from a spreadsheet somebody superseded a fortnight ago. Every one of those starts as a harmless extra copy, and every one of them has cost an Australian business real money and real embarrassment.