Hello, the team of WP8 Kuqi. com will answer your questions:

If your mobile phone is wp8.1, press the win key+Volume Down key at the same time. If you have upgraded to the developer preview version of wp8.1, please press the win key+Volume Down key at the same time, so that you can take a screenshot.

if you don't understand, please ask, and if you are satisfied, please adopt!