By convention, the direction of current in a circuit is

The direction of motion of positive charge carriers

Explanation:

A current is defined as a flow of charge carriers. The formula to calculate the current is

where q is the amount of charge passing through a given point in a time interval of t.

However, the charge carriers can be of positive charge or of negative charge. Therefore, in order to avoid ambiguity on the direction of the current, it has been established that the direction of current is that obtained if the charge carriers are positive in charge.

This means that if the charge carriers are electrons (which have negative charge), as normally in electric wires, then the direction of the current is opposite to the direction of motion of the electrons.