You can apply fade-ins, fade-outs on any type of layer, and create crossfades between adjacent clips within a layer. Crossfading is the process of fading between two clips and helps smooth out transitions by preventing audio pops and clicks.
Creating and adjusting fades and crossfades
Adding a crossfade or fade over all layers in a scene
If you want to fade or crossfade all layers within a scene simultaneously, you'll want to apply a transition on the scene.
You can quickly create visual and audio fades and crossfades by dragging a transition handle in the Timeline.
You can adjust and apply fades or crossfades by clicking on the transition handle of your clip.