Abstract: The imaging technology is being improving day by day, there are a lot of chances of reproduction and manipulation of digital contents such as digital image, digital audio and digital video, hence a strong digital copyright mechanism must be developed in place. So the protection of data content from unauthorized users and the issue of copyright management play very important role. Digital watermarking is being used to secure the data of researchers and to hide the information inside a signal which cannot be easily detected by unauthorized users. A digital watermarking can be defined as a stream of bits embedded in a data file that offers features such as IPM (Intellectual Property Management) and proof of ownership. The digital watermarking has two basic concepts- first is content protection and second is copyright management. In this paper, an overview of some Digital Watermarking techniques is discussed such as Discrete Cosine transform (DCT) and Digital Wavelet Transform (DWT) and its purpose, methods, limitations and applications.