Fade IN or OUT the volume !!!

Hi All 

I remmeber in 2017 or 2018 i created a shortcut to Fade the volume IN or OUT by just pressing the shortcut and make the sure my timeline indicator where i want it to be. For example if i put my indicator 1 second before the end of the Clip and presss the shortcut it will fade the volume starting from my indicator position till the end of the footage, and vise versa for the Fade IN, just like in the image attaced. 

I just cant find it in the keyboard shortcut or i just forgot how, any Ideas ? 

Best, 

Mo