The Xbox One still doesn't boast the ability to capture screenshots, but the feature is on the way.
See The Smite Season 2 Change List Here
Xbox head Phil Spencer teased screenshots on the new console via Twitter, noting that he's now able to use the feature on his dev kit. As it stands, it appears that you bring up the screenshot option by double-tapping the home button, where the Xbox's snap menu resides.
responses by explaining screenshots are still in the debug stage, meaning it and the accompanying UI process are subject to change. Xbox will talk more about the feature "soon".
Our Review Of Techland's Excellent Zombie Survival Title, Dying Light
PlayStation 4 has boasted screenshots since day one, using its share button to snap a picture or save the last few minutes of video. They can be saved onto a hard drive and moved with USB, or uploaded to Facebook. At this time, it's not clear what you'll be able to do when saving an Xbox screenshot.