Can I set file permissions for members of my shared folders?
Basic (free) users: All members of your shared folders can add, edit, or delete files in those folders. If you'd like to share a file or folder for people to view or download only, send a link to it instead of inviting people to a shared folder.
Dropbox Pro and Dropbox for Business users: If you own a shared folder, you can prevent other members from adding, editing, or deleting files in the folder by setting view-only permissions.
Setting file permissions on your computer
If you've used your computer's file manager to make a file read-only, please note that some permissions settings are incompatible between operating systems. For example, a file with read-only access on your Windows computer may not be protected on a Mac. Dropbox doesn't change a file's permissions when syncing, but we can't guarantee the permissions you set in one operating system will work properly when opened in another operating system.