“Step-and-repeat” is the term used for the process of duplicating an object and spacing. Typically step and repeat is used in an object-oriented program, such as InDesign, rather than in a pixel-based editor, such as Photoshop. However, you can indeed replicate a step-and-repeat technique in Photoshop.
Let’s work with the example of creating a series of evenly spaced pawprints. I added a new empty layer to the image, then used the Custom Shape tool to create a couple of paw prints. (Remember that the Custom shape tool’s behavior is governed in the Options bar with three buttons. Select the first button to create shape layers, the middle button to create work paths, the third – the one we need for this example – to add pixels to the active layer.)
Hold down the Option/Alt key and press the keyboard shortcut for Edit> Free Transform, Command-T (Mac) or Control-T (Windows). Adding the Option/Alt key to the shortcut enables to make and transform a copy of the pixels rather than transforming the original. This will give us the next pair of pawprints. With the transform bounding box active, click on the layer content and drag to duplicate and reposition. Press the Return/Enter key when done.