Today’s world is digital world. Nowadays, in every field there is enormous use of digital contents. Information handled on INTERNET and MULTIMEDIA NETWORK SYSTEM is in digital form. The copying of digital content without quality loss is not so difficult .Due to this , there are more chances of copying of such digital information. So , there is great need of prohibiting such illegal copyright of digital media. Digital watermarking (DWM) is the powerful solution to this problem. Digital watermarking is nothing but the technology in which there is embedding of various information in digital content which we have to protect from illegal copying. This embedded information to protect the data is embedded as watermark. Beyond the copyright protection, Digital watermarking is having some other applications as fingerprinting, owner identification etc. Digital watermarks are of different types as robust, fragile, visible and invisible. Application is depending upon these watermarks classifications. There are some requirements of digital watermarks as integrity, robustness and complexity.