The best time to apply copyright presets is when you import photos into your Lightroom catalog. There’s an option for this in the Apply During Import section on the right side of the Import dialog. For images that are already in the catalog, use the Preset drop-down menu in the Metadata panel to apply a saved metadata preset to either a single image or a group of selected photos.
This tip originally appeared in the Tips & Tricks column by Seán Duggan, in Lightroom Magazine issue 37.