Can we say that monetary policy is for financial system?

Sort of. The goal of monetary policy is to stabilise the economy by controlling interest rates and the supply of money. Fiscal policy, on the other hand, is the use of government spending and tax collection to influence the economy. Given that most monetary policy is controlled by a central bank, your could say monetary policy is for the financial system although your question is not entirely clear about the extent you wish to make this ertion.