HTC One Remix - Manual (Page 56)

Capturing your phone's screen
Want to show off your high game score or write a blog post about
HTC One remix features? It's easy to take a picture of the screen and share
it from Gallery.
Press and hold POWER and VOLUME DOWN at the same time.
The image is saved in the Screenshots album in Gallery.
You can also share the image when you see in the status bar.
Open the Notifications panel and tap under the screenshot
notification. If you don't see , slide two fingers apart on the
screenshot notification.
56 Your first week with your new phone