Every tonal and color change made through the Image menu is permanent — once applied, those edits are baked into the pixels with no way to revisit individual settings. Adjustment layers solve this by keeping each change on its own editable, maskable layer, so nothing in the original image is ever
Read the full article here: Image Adjustments vs Adjustment Layers in Photoshop: Destructive vs Non-Destructive Editing Explained Photoshop Roadmap