If I save a file from my laptop to a usb stick then upload that file on another computer, does the file record data identifying the machine it was created on or does the file's source remain anonymous?
Depends on the file and what software was used to create it. E.g., if you inspect the properties of a Microsoft Office document which you created, you'll almost certainly see your own name as the document creator.
Thanks for both answers. I found details under 'Properties' but on the 'Details' tab there's an option to 'Remove Properties and Personal Information'.