I'm trying to somehow allow other people to download uploaded files on QuickBase on a different website. I have files on QuickBase uploaded, but people need to sign-in to QuickBase to download it. Is there any other way around it?
You can grant what is essentially anonymous access to one of your Quickbase applications by giving "Everyone on the Internet" a role in your application. It gives anyone with a link to that application whatever access level is defined in the role given. If you want to only share files, you could create a role that has view only access of that specific file attachment field and assign that to "Everyone on the Internet". If you want to be selective about which records are available for download you can include a checkbox to "Make Public" and include that in the role's view logic.
You grant "Everyone on the Internet" access in the add user form for the application. If you start typing "Everyone on the Internet", you'll see it pop up as a recommended user name. If you do not see this as an option, that means that granting open access was disabled by one of your billing account administrators.
Just remember, whatever permissions you grant "Everyone on the Internet" applies to literally anyone on the Internet that has a link to your app. Of course, you can always use a separate file hosting service like Dropbox or Box if you want to avoid the Quickbase issue entirely.