Hi Murat!

If I have n qubits, the quantity of quantum states is 2^n. Therefore, if I have 2 qubits then I have 4 quantum states.

This post also answers the question: https://cosmosmagazine.com/science/quantum-computing-for-the-qubit-curious/#:~:text=Two%20bits%20in%20your%20computer,%2C%2010%2C%20or%2011).