While C corporations and S corporations are similar in how they operate, they differ in their taxation. In forming your corporation, these tax considerations are often a big factor when choosing a structure.
C corporations pay tax on corporate profits, and its shareholders are taxed on the dividends paid out.
With an S corporation, profits and losses are passed through to the shareholders to be reported, and if applicable paid, on their personal tax returns, similar in some respects to default LLC taxation.
C corporation is the default; a corporation may elect S corporation status through a filing with the IRS.