Question

In case of charge why it flows from negative to positive? In all other case's flow is from positive to negative.

Answer 1

Energy always flows from higher potential to lower potential.
The particle responsible for electricity is the electron which has a negative charge. In a battery, the negative terminal has an excess no. of electrons and the positive terminal has a deficiency of electrons. When the two terminals are connected, the electrons will start to flow from negative to the positive terminal the battery (then back to the negative, internally in the battery). Hence as the electric current notation depends on moving direction of electrons, the E. Current flows from - ve to +ve
It doesn't matter in the electronics (only in some cases like motor operation will be depended on it). You can actually imagine electricity flowing either +ve to - ve or from - ve to +ve and you'd get the same result
But coming to the case of electrical devices like diodes and transistors, the notion of electricity is shown as from +ve to - ve. What it means is that flow of ‘space lacking electrons’(holes) from +ve to negative (in reality, only the electron moves. These “holes” are not actual particles, they’re simply a tool used to help imagine positive-to-negative flow.