As there is no Home button on iPhone X, how do you take a screenshot?
Swiping up from bottom of the screen while pressing the lock button?
Hold the Side button and tap Volume Up.
#iPhoneX screenshot: Side button + Volume up
Two Methods i found on Google,
Using Press, Side Button + Volume Up button at once.
Using Assistive touch, Really great for use on lock screen, Home screen or App Screen.