Individual income tax shall be declared by itself in the year of comprehensive income. Self-declaration of comprehensive income during the year refers to the normal tax deduction when the unit pays wages every month, and then the taxpayer himself goes to the tax authorities for special additional tax deduction in the second year, and then the tax authorities refund the tax, which means that the tax deduction is normal when the unit pays wages every month, and then the taxpayer himself goes to the tax authorities for final settlement and payment in the second year, and provides relevant information to the tax authorities for tax refund. Through the annual comprehensive income self-declaration, everyone needs to apply for deduction, which will be more troublesome, and they can't enjoy tax reduction in the same month. But for people with multiple incomes, it will be better to apply for it yourself.