They are the same in so far as watermarking is a special case of a more general technique. The message communicated secretly by a watermark is "This is Bob's Image!" Which I know sounds like "all cats are mammals, not all mammals are cats" sort of semantic word play.

They are merely same the only difference is the difference between watermarking and steganography approaches and the way you look at them or use them.

Thank you Robert Mahar Sir, Atta ur Rahman Sir, Zubair Jeelani , Baydaa Mushgil .

In stego. It's a matter of transmitting binary data imperceptibly . While in watermarking, the data should be safe as well. So each watermarking method need to be supported with security technique for the embedded data.

Both are same when the watermarking is an invisible technique. Both replace the LSBs of embedding contents, for example image pixels. The objective of image steganography is to provide the secrecy of the implanted data. The steganography always hide the data. On the contrary, watermarking provides the integrity of the cover objects. That technique also implants a marker in an object, named cover. The marker may be visible and invisible in the cover. If the marker is invisible, then the process of steganography and watermarking are same. Only they works from different objectives.