Keyboard shortcuts are available to perform common tasks in ArcGIS Web Editor. You can open a list of the available keyboard shortcuts using the Shortcuts button 
or by pressing Alt+? on Microsoft Windows or Option+? on Mac. You can also enable shortcut keys in tooltips for editing tools in the Settings pane.
Note:
If the Shortcuts button is not visible, it may mean shortcuts have been turned off in the Settings pane.
Learn more about Web Editor settings