What is electric current? What conditions are necessary for its existence?

Electric current is the directed movement of charged particles. The direction of the current is taken as the direction of the positively charged particles.
The conditions for the existence of an electric current: 1) the presence of combined charges, 2) the presence of an electric field in the conductor.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.