Technical analysis is a discipline in trading that employs mathematical functions, called technical indicators, to predict and find profitable opportunities in stock markets. Technical indicators analyze data based on past and current prices and volumes of a financial instrument and give out statistical information. This helps in predicting where the future prices of a financial instrument may go (either up or down). With this knowledge, you as a trader can make informed decisions when trading and hence increase your odds of success.
Technical indicators do not take into account any of the fundamental aspects of the business of the underlying financial instrument, such as revenue, earnings, profit, ...