From the beginning of history until now, human life has been full of ups and downs to achieve perfection and progress. . It is obvious that the old methods of production and distribution of knowledge, which are designed based on face-to-face communication, are gradually losing their effectiveness and the need to use new tools is felt. In order to meet this need, e-learning, which is an evolved form of the old methods of teaching and learning using information technology, was introduced in the early decade and quickly introduced as the superior method of learning in the age of knowledge and awareness. E-learning is actually learning through computers, multimedia computer networks and the Internet, which has become accessible thanks to the increasing growth of information technology. E-learning will move the learning process from traditional classroom to online learning and will bring many benefits to the learner and the organization. Time and place in e-learning teachings lose their modern meaning in traditional classroom methods, meaning that there will be no time or space constraints. In this article, we examine the characteristics, factors and challenges facing e-learning, and analyze it from different angles, and we will try to explain and present it as much as possible.