How does your company handle expense report attachments?

The "attach file" function when submitting an expense report appears to access every folder and file that isn't restricted in the file cabinet. My question is, how do you manage this? Do you create an individual folder for each employee? Do you use a single folder and let all employees have access to everyone's receipts? Do you have issues with employees saving receipt files in the wrong folders?

Any response is helpful, thank you!