If other users require access to a file, the uploader must share the file with them. This can be done either at the time of upload or later on once the file exists in the system.
Share Files at Upload
When you upload a new file, there will be an option to 'share with staff or groups'. Toggle this on to enable the search bar below it. From here, you can select individual users or staff groups to share the file with.
Alternatively, tick the 'admins, line managers and this employee' or 'admins and this employee' option (this will depend on your company settings).
Share Files After Upload
To share a file after it has been uploaded, you will need to navigate to the area it was uploaded to (either the Company Files page of a user's profile).
Find the file and hover over it, then click on the cog that appears to the right of the page.
You can then choose who you wish to share the file with. If there are already users with access to the file, you can choose to remove them by clicking the 'x' next to their name.