An adjustment layer is a special type of layer in Premiere Pro that allows you to apply effects and adjustments to multiple clips simultaneously. This can be a powerful tool for color correction, color grading, and other effects. To add an adjustment layer, simply click on the “New” button in the Timeline panel and select “Adjustment Layer”.
Adjustment layers are non-destructive, meaning that they do not permanently alter the original clips. This makes them a great way to experiment with different looks and effects without having to worry about damaging your footage. You can also use adjustment layers to create complex effects that would be difficult or impossible to achieve with other methods.