Can iOS apps read your clipboard, and can it be stopped?
Any iOS can always access the clipboard, there isn't really a way to prevent this from happening. Recent iOS versions show a little info box at the top of the screen when this happens so you should be at least aware if an app does this &quot;in the background&quot;.
PS: An app can not access clipboards on other devices. What happens with Handoff is that the clipboards are synced across devices by the OSes (macOS and iOS) in the background so that at the moment an app access the clipboard it may get the content you just copied into it a few seconds ago on your Mac.