If a supplier sends a statement of account can this be added in under their account

You've come to the right place, @Gerard9.

I know a way that can add your supplier's statements to their profile.

QBO lets you add attachments, however, it cant be attached directly to list items like Accounts but rather keep it in your supplier's profile.

Let me show you how:

1. Go to Get paid & pay and select Suppliers .
2. Choose a supplier, then select the Supplier Details tab.
3. Select Attachments.
4. Browse and select the file you want to attach, then select Open.

You'll want to check out this article to learn what types of files can be attached to QuickBooks: Add or delete attachments in QuickBooks Online.

Keep me posted if you have any other concerns or further questions. I'll always have your back.