If you have a C corporation that files Form 1120, you only report compensation (including wages, bonuses, and taxable fringe benefits), dividends, and other taxable distributions received. The corporation itself pays tax on its profits. However, if you have an S corporation, in addition to reporting compensation and dividends, you also report your share of corporate profits on Schedule E of Form 1040. The amount reported on Schedule E is taken from Schedule K-1 issued to you by the S corporation.
This is generally adjusted gross income increased by certain items such as tax-free foreign earned income. MAGI usually is used to determine phaseouts of certain deductions and credits.