Pressing Alt-Tab cycles through all open app windows. You can also click or tap the Task View icon on the taskbar and point to and click or tap the app you want.
"Win10 Switch apps." YourDictionary, n.d. Web. 14 August 2018. <http://www.yourdictionary.com/win10-switch-apps>.
Win10 Switch apps. (n.d.). Retrieved August 14th, 2018, from http://www.yourdictionary.com/win10-switch-apps