In Photoshop, an adjustment layer is a layer that allows you to make changes to your image without permanently altering the pixels. Adjustment layers are non-destructive, meaning that you can always go back and make changes to them without affecting the underlying pixels.
There are a variety of adjustment layers available in Photoshop, each of which allows you to make a different type of change to your image. For example, you can use an adjustment layer to change the brightness or contrast of your image, or to add a color cast.
To create an adjustment layer, simply click on the “Create new fill or adjustment layer” button at the bottom of the Layers panel. Then, choose the type of adjustment layer you want to create from the menu that appears.
Once you’ve created an adjustment layer, you can adjust its settings by double-clicking on the layer in the Layers panel. This will open the Adjustments panel, where you can tweak the settings for your chosen adjustment layer.
When you’re happy with your adjustments, simply click on the “OK” button to apply them. Remember, because adjustment layers are non-destructive, you can always go back and make changes to them later if you need to.