There is no native button object in Qlik Sense but you can create buttons using extensions. There is an example provided in the Qlik Sense desktop installation that provides buttons for Clear All, Back and Forward. The example is located in C:\Users\<name>\Documents\Qlik\Examples\Extensions\ToolBar. Copy the ToolBar folder to C:\Users\<name>\Documents\Qlik\Sense\Extensions and you will be able to add the toolbar buttons to a sheet like any other object.
Some typical operations used with buttons are found in the App- API
And the navigation API
You need an extension for this and is not implicitly available in QlikSense.
Check these out: