Electron flow theory
You will find actually two theories related to current flow. One theory is termed the electron flow theory and states that since electrons are negative particles, current flows from the most negative point in the circuit to the most positive. The electron flow theory is the more commonly accepted as being correct.
Conventional current flow
An additional theory, known as the conventional current flow theory, is older than the electron flow theory and states that current flows from the most positive point to the most negative. Even though it continues to be established almost to a certainty that the electron flow theory is correct, the conventional current flow theory is still widely used for several reasons. Many electronic circuits utilize the negative terminal as ground or common. When the negative terminal is used as ground, the positive terminal is considered to be above ground, or hot. It is easier for most people to think of something flowing down rather than up, or from a point above ground to ground.