The answer depend on how $\mathbb{C}$ is defined!
One way is as the quotient field $\mathbb{R}[X]/(X^2 + 1)$ of the ring of polynomials in one variable over $\mathbb{R}$ modulo the ideal generated by $X^2 + 1$, and then you may define the "identification" shown in the answer by A. Pongrácz, i.e., set up a bijection between the set of complex numbers and the set $\mathbb{R}^2$.
On the other hand, a simpler way is to define $\mathbb{C}$, as a set, to be the set $\mathbb{R}^2$ of ordered pairs of reals, and then that "identification" is in fact the identity map!
The distinction between $\mathbb{C}$ and $\mathbb{R}^2$ as algebraic systems comes only once you define the field operations on the first and the vector space operations on the second.