How do you create a clipping mask in Photoshop?

Creating a clipping mask in Photoshop is a technique that allows you to control the visibility of one layer based on the content of another layer. When you use the "Create Clipping Mask" option from the Layers menu, you are essentially linking the upper layer to the lower layer, which determines how the upper layer displays itself within the boundaries defined by the lower layer.

When you select the "Create Clipping Mask" function, the layer above the base layer takes on the shape or transparency of the layer underneath it. This is especially useful for creating effects such as text filled with an image, as the image will only show through where there is actual content on the lower layer.

Other methods such as merging layers do not create a clipping mask, as this action combines layers into a single one rather than allowing one layer to interact with another in a specific masking way. Adding a layer style refers to adjustments like shadows or glows but does not involve the masking functionality needed here. Additionally, dragging one layer under another doesn't inherently create a clipping mask; without the specific action of using the "Create Clipping Mask" command, the layers simply stack, preventing the intended masking effect.