Stop sharing files
It’s easy to share a file or folder but it’s not obvious how to then stop sharing it. On the IOS app, tap the file’s menu button and select Details. At the bottom, it lists people with access, such as ‘Anyone with this link’. Tap it, then tap Remove Access.
On Android, tap the menu button, then the tiny ‘i’ in the corner to display information about the file. The people it is shared with are listed at the bottom. Tapping them cancels sharing.