Hi and Welcome. My Name is ***** ***** I look forward to assisting you today with your question.
First we can reset your iPad and see if it works or not. Press and hold down the Power button and Home button at the same time until it shows the Apple logo. When you see the Apple logo, release the buttons and let it boot.
Then delete the Docs app if it is there. Then redownload it from App Store. If that didn't work, then go to Settings> General > Software Updates and do all updates from there.
Please let me know if that didn't work, so we can continue troubleshooting.
Also what is the exact name of the Docs app you've downloaded ?