First, make a copyright watermark.
Copyright watermark is a pattern or text that can reflect the culture of the copyright owner and represent the mark of the copyright owner, also known as LOGO, and is called symbol pattern or hieroglyphics. Any form of logo, if registered, is protected by law and is called "trademark".
Watermarks are generally saved in PNG format, and the background is transparent.
Second, the use of watermarks.
In PHOTOSHOP, open the original image and file placement, place the watermark image, adjust the size and position, and finally merge the layers.