If your wanting to watermark your photos then you need an image editing program to do so, use the text tool to put the copyright text onto the image, preferably onto a different layer so as not to damage the original image, once you have the text you can then lower the opacity to make it less visible.
Make sure that you save the image under a different name so you do nor over write and spoil your original.
All photographs are copyright-protected - you don't need to put any symbol on them. Copyright in all photographic images is automatically vested in the person who took the photograph, unless he/she signs an agreement to the contrary.
Most people aren't aware of this, but it's a fact. If you engage a wedding photographer the copyright in your wedding photos belongs to him or her - not to you.