I want to donate my old iPad and so far, i am unable to erase my personal files and set ups using "Settings" Please help

I would like to donate my old iPad to my company for use. I have gone to "Settings" and followed all of the instructions to erase and reset my iPad, but when it asks me to sign on to my ITunes account, it won't take my password. (I had already removed that device from my account.) How do I proceed from here to clear off and reset my old iPad?

Thanks.