How do I put my name across the pictures of my cake.( I believe it's call water mark)

Thanks

AI use Photoshop so I can play with transparency to reduce its impact but you could have a look at some of these: https://www.google.co.uk/#q=free+watermark+tool

What i use is a software called Mass Watermark add your pics(many at a time),type in the watermark,choose the placement.Click go.There are many other settings to check out.Take a look at this Video