HTC One M9 - Manual (Page 35)

Press and flick
On the Home screen, you can easily move a widget or icon from
one screen to another.
Press and hold the widget or icon with one finger, and flick the
screen to the new location with another finger.
Slide with two fingers
In some apps, like Gallery, Messages, Mail, or
the web browser, slide two fingers apart to zoom
in when viewing a picture or text.
Slide two fingers together to zoom out of the picture or text.
35 Your first week with your new phone