Lumia 640 to take a screenshot with Volume Up Button with Power Button press and wait. Your phone will take a screenshot and save it.
Operating system on Microsoft’s Lumia models Windows 8.1With the upgrade to , the screenshot process has changed. Screenshots that used to be taken with Windows Key and Power Button are now taken with Volume Up Button and Power Button.
Lumia 640 to the screenshots you have taken with Photos > Albums > Screenshots You can access it from the tab and perform the necessary actions.