If you want to hide Top Bar, Ribbon, Quick Launch are come up with Application Pages by default.

One way to hide these controls is by passing a Parameter with the URL. [ ?IsDlg=1 ] SharePoint will hide these elements when It gets IsDlg Parameter on URL.

Or you can create a css file and add it in by Content Editor Web Part

<style type="text/css">

    #s4-ribbonrow, .ms-cui-topBar2, .s4-notdlg, .s4-pr s4-ribbonrowhidetitle, 
.s4-notdlg noindex, #ms-cui-ribbonTopBars, #s4-titlerow, #s4-pr s4-notdlg 
s4-titlerowhidetitle, #s4-leftpanel-content {display:none !important;}

    .s4-ca{margin-left:0px !important; margin-right:0px !important;}


#This will hide the elements and only the content will be shown.

Note : If you use this code in SharePoint Site Pages with Content Editor Webpart then you can’t check in the page since the toolbar goes hidden.

[ ?Contents=1 ] will opens the page in WebPart maintenance mode to help you remove web part easily.