Premiere Clip does not do any green screening or chromakeying in the app. You can use Premiere Clip to shoot against green screen and build up your rough cut, and then choose Edit in Premiere Pro to access the tools in Premiere Pro. Here's a tutorial: Try out three keying effects | Adobe Premiere Pro CC tutorials
Hope this helps!
Which of the Adobe apps CAN do green screening or Chromakeying? I want to do this on an ipad. I have the entire Creative Cloud, I would just like to know which app to download to key out the green. Thanks!