Click the Model tab in the lower-left corner of the application window.
If the Model and layout tabs are hidden, click the Model button on the status bar at the bottom of the application window.
If you want to access model space from within a layout viewport, double-click inside the layout viewport. When you are done, you can click within any other layout viewport to make it the current one, or you can double-click anywhere else in the layout to return to paper space.
