I have cleared data of download manager app but still it is showing and I also tried formatting phone after formatting it works but wen I download something it's not working
Welcome to Android Central! Which phone? What's the exact error message you're getting? "Documents" isn't directly related to the Download Manager app.
Hmm -- maybe "Documents" is what that phone calls its file manager app. Try going to Settings>Apps, tap Menu>Show System, and look for an app called Documents. Clear the cache and data for that app as well, and then see if the the problem goes away.