A Microsoft file hosting and synchronization service.
After a long time, I found a quick solution.
I deleted my Samsung account. Then I restarted. Now OneDrive works perfectly.
I had tried everything else. Reset the apps by deleting data and cash. Uninstall and reinstall apps. Remove the connection of Samsung to the Microsoft account. Remove permissions of Samsung Gallery. Enable permissions of OneDrive. Restart the phone multiple times. Samsung Gallery kept screwing OneDrive. Nothing worked. I did not uninstall the Office apps, but problem solved.