Hi, welcome to iMore.
Unfortunately it's not possible to label videos and photos in the Photos app on an iPad or iPhone.
iOS 10 automatically sorts photos and videos based on date. It also sorts on face, which you can find under Albums. You can even specify who that person is and so on.
Please take your time to read the following guide:
http://m.imore.com/photos?client=safari
If you have any further questions, please join our forum. We're happy to help.